The Roman Rule Testis Unus Testis Nullus in the Canonical Codified Sources Regulating Ordinary Proceedings

Abstract

This article presents the issue of the Roman procedural rule testis unus testis nullus in the canonical sources regulating ordinary proceedings. The rule on witnesses found its place in the 1917 Code of Canon Law, and was later repeated in the 1983 Code of Canon Law and in the 1990 Code of Canons of the Eastern Churches. It was included in the section of the code containing canons regulating contentious proceedings and has been applicable as a general norm. It was pointed out that the Roman principle of witnesses had been a very important reference in the legal tradition of canon law for centuries, but it was not applied in a formalistic manner and deviations in its application were allowed. However, this practice was not entirely in line with the biblical tradition, nor with the Roman tradition, especially since the issuance of the imperial constitution by Constantine the Great in 334. This article attempts to answer the question why the canonical tradition, which has adhered to the requirement of testis unus testis nullus for centuries, does not do so in an absolute manner, allowing for the possibility of exceptions. In this regard, selected fragments of two imperial constitutions of Constantine the Great are presented and analysed. They regulated the issue of the universal requirement of double testimony in imperial law and the admissibility of a single testimony delivered by a bishop.

1. Introduction

Pope Benedict XV, announcing the first Code of Canon Law in the Church by virtue of the bull Providentissima Mater Eccelsia of 1917, recalled the objectives of the Church’s legislative activity and indicated ways of achieving them. In this context, he emphasised with appreciation the important role of Roman law, recalling that it has long been rightly referred to as ‘ratio scripta’ (reason incarnate).1 He then stated that, with the help of God’s light, the Church had also corrected and marked with Christian perfection Roman law itself, which is a distinguished monument of ancient wisdom (insigne veteris sapientiae monumentum).2 What resonates strongly in the context of the above papal statement is the well-known Latin maxim Ecclesia vivit lege Romana (Burczak et al. 2013, p. 66). The principle that the Church lives by Roman law constantly reminds us of the significant value of Roman law and its prominent place in the centuries-old canonical tradition of the Church (Di Ponzio 2019, pp. 17–19).

However, it should be added that biblical sources have been another important model and point of reference for ecclesiastical legislators throughout the centuries. This was emphasised by John Paul II in the Apostolic Constitution Sacrae disciplinae leges of 25 January 1983, which promulgated the second Code of Canon Law in the Church. The Pope noted that the legal and legislative tradition of the Church has its primary source, to a certain extent, in the impressive and long heritage of law contained in the books of the Old and New Testaments. He then emphasised that Christ the Lord not only did not question or destroy this heritage of the Law and the Prophets, but fulfilled it. Moreover, he gave it a new and more perfect meaning, which was recorded and preserved in the New Testament.3

The impact of these ancient legal traditions on canon law was significant. According to the eminent Romanist and canonist Stanisław Płodzień, this influence was particularly evident in the field of ecclesiastical procedural law. He convincingly argued that bishops who, by virtue of an imperial mandate, exercised judicial authority (episcopalis audientia) in the first centuries had to take into account, to a considerable extent, not only evangelical principles and the requirements of local Jewish law, but also Roman law (Płodzień 1959, p. 5). A good example of mutual inspiration in this field was, among other things, respect for the rule of evidence prohibiting the acceptance of single testimony in court cases. The Church’s consistent stance on maintaining the requirement of double testimony was justified by the fact that the principle was established in Mosaic law4 and reiterated several times in the books of the New Testament.5 In addition, it was also confirmed by Constantine the Great, the first Christian emperor. In 334, he decreed that a similar evidentiary requirement should apply in the cognitio procedure of Roman law throughout the Roman Empire. Hence, ecclesiastical legislators never questioned the rationale for the existence and significance of this rule. Furthermore, they sought to ensure that it was applied and observed with due diligence. Failure to comply with the requirement of double testimony in a trial was considered a serious procedural irregularity, which even resulted in the invalidity of the judgment (Wacke 1997, p. 51).

The rule regarding witnesses, both in biblical sources and in post-classical Roman law (from the law of 334 AD by Constantine the Great), was formulated definitively and did not allow for any exceptions. It is significant that for centuries the Church has adhered to the requirement of testis unus testis nullus, but at the same time this was not performed in an absolute manner and certain exceptions were allowed. It is interesting that this tradition was alive for centuries in pre-code canon law, and was also adopted and respected in the procedural provisions of the canonical codes issued in the 20th century in the Church.

2. The Rule of Testis Unus Testis Nullus in the Legislation of Emperor Constantine the Great

The introduction of the double certificate requirement in Roman law was a rather long and complex process. It should be understood that it was finally formally completed in 334 in connection with the proclamation of the constitution by Constantine the Great (Metro 2001, pp. 114–15). The emperor decreed as follows:

We have previously decreed that witnesses should be required to take a solemn oath before giving testimony and that greater trust should be placed in witnesses of higher standing. Similarly, we have decreed that no judge should readily admit the testimony of a single person. Now, we clearly establish that the testimony of a single witness should not be heard at all, even if such a witness enjoyed the respect of the renowned curia. This occurred on 25 August 334 in Nis, during the consulate of Optatus and Paulinus.6

The imperial law was universal and binding. It partially repeated and confirmed the provisions previously issued by Constantine the Great. The emperor reiterated the requirements concerning the personal characteristics of witnesses, their number in a case, and their obligation to take an oath. In addition, he pointed to the greater value of the testimony of persons enjoying greater trust in society (honestiores) (Padoa-Schioppa 1967, pp. 335–37). The third provision was a novelty not only in the field of jurisprudence, but also, it should be emphasised, in terms of normativity. It definitively established the inadmissibility of the testimony of a single person, even if they belonged to the prestigious group of honestiores and enjoyed considerable authority in society. The uniqueness of the solution proposed by Constantine the Great was manifested in the fact that from then on, evidence from the testimony of a single witness in a trial was to be considered by the judge not so much as unreliable, but as inadmissible (Loschiavo 2004, pp. 36–37).

From the perspective of the issue under consideration, it is reasonable to refer to another imperial constitution of Constantine the Great, which dates back to the year 333. It was later named the first constitution of Sirmond (Di Ponzio 2019, pp. 70–71). The regulation was crucial in establishing the institution of episcopalis audientia (Joźwiak 2016, pp. 136–37) and the obligation of judges of state courts to honour this authority. It included an important provision concerning testimonium episcopi, referring to the power and value of a single testimony presented by a bishop (Biondi 1952, pp. 450–51). The emperor, addressing one of his most important officials, who exercised judicial power in the state on his behalf, wrote:

All cases examined according to praetorian or civil law and concluded with the judgments of bishops shall be permanently enshrined in law, and no proceedings concluded with a bishop’s judgment shall be allowed to be reopened. The testimony of even a single bishop shall be accepted by every judge without question, and no other witness shall be heard, since the testimony of the bishop shall be recognised by both parties.7

The motives that prompted the emperor to issue two constitutions within a few months, which were inconsistent in terms of the strictness of the established requirement, have generated much discussion and even controversy among researchers (Archi 1961, pp. 3–23; Cimma 1989, pp. 5 ff.; Metro 2001, pp. 109–16; Odrobina 2003, pp. 41–62; Pilara 2004, pp. 353–78). An interesting attempt to explain this problem was presented by Italian researcher Antonino Metro. In his opinion, bishops did not simply fall under the universal rigour of the testis unus testis nullus principle introduced by the law of 334, because they were representatives of the Church, which, after gaining religious freedom, was gaining increasing influence and prestige in the state. The quoted passage from the constitution clearly stated that the testimony of one bishop was so strong that there was no need to seek a second witness. In the emperor’s opinion, clergy representing the authority of the Church were considered credible and righteous. It is possible that the ruler decided that there was no need to apply to them the provisions requiring the necessary examination of such requirements as credibility or the number of witnesses (Metro 2001, p. 115). Hungarian researcher Laszlo Odrobina expressed a similar view. He rightly argued that since the introduction of the universal rule of evidence testis unus testis nullus in August 334, there was one case in which it was possible and valid to accept the testimony of a single witness in a cognizance trial. However, two conditions had to be met. The witness had to be a bishop and could only testify in relation to the circumstances contained in a decision that he had previously issued personally in a specific case within the confines of espiscopalis audientia (Odrobina 2003, pp. 61–62).

It is worth noting that the aforementioned regulation from 333 opened a collection of 16 imperial constitutions, which were later referred to in the doctrine as the Constitutiones Sirmondianae. They were issued from the late reign of Constantine the Great until the reign of Valentinian III and constituted an important source of law for the Church (Cimma 1989, pp. 40–41). Among other things, they regulated important issues related to religious life and the exercise of power by the clergy (Pilara 2004, pp. 356–58).

Officially established by Constantine the Great in 334, the evidentiary requirement was subsequently adopted in the Code of Theodosius II8 and the Code of Justinian.9 It is noteworthy that after the fall of the Roman Empire in 476, the rule of witnesses continued to be applied in the West, and later, when applied in the common law system (ius commune), it successfully permeated the Roman medieval tradition. In the East, the rule remained in force for centuries in Byzantine law (Padoa-Schioppa 1967, p. 335). It was not until the 19th century that it began to lose its significance and relevance, especially in secular legal systems in Europe. Nevertheless, in pre-code canon law, the requirement of two witnesses retained its vitality and significance for centuries. It was also included in three canonical codes of the 20th century (Sadowski 2007, pp. 34–43).

3. The Rule of Testis Unus Testis Nullus in the Codified Sources of Canon Law

The principle of testis unus testis nullus found its prominent place in the first Code of Canon Law of 1917, known as the Pio-Benedictine Code. It was included in the fourth book regulating procedural law as a general rule.10 Therefore, it was somewhat a natural consequence that it was repeated in two subsequent significant ecclesiastical codifications in the 20th century. It was included in the new Code of Canon Law of 1983, and a few years later in the Code of Canons of the Eastern Churches, which came into force in 1991.11 It should be noted that with each new regulation, the ecclesiastical legislator, recalling the rule of testis unus testis nullus, retained the essence of this evidentiary construct, although sometimes giving it a slightly different wording or formulation (Grzywacz 1985, pp. 19–20).

In the Pio-Benedictine Code, the issue of the value of a single testimony was included in can. 1791 § 1–2 CIC/17. It read as follows:12

§ 1 The testimony of a single witness does not constitute full evidence, unless the witness is a qualified witness testifying about matters performed in an official capacity.

§ 2 The testimony of two or three credible witnesses who, under oath and on the basis of their own knowledge, testify before the court in complete agreement about the same thing or the same fact constitutes sufficient evidence. In very important cases or in the event of circumstantial evidence raising suspicion as to whether the truthfulness of the statements has been sufficiently proven, the judge may require more complete evidence.

In the quoted passage, the ecclesiastical legislator indicated two guidelines, negative and positive, which constituted strictly binding instructions for the judge. The negative aspect meant that the testimony of one ordinary witness, assuming that there was no other evidence, could not be accepted as full proof (Conde 2006, pp. 463–64). The rationale behind adopting such a structure was a consequence of the earlier recognition that consistent testimony from at least two credible witnesses constituted sufficient evidence to pass judgement. In light of the above, by reasoning a contrario, it was obvious that a single witness did not constitute sufficient evidence (Myrcha 1936, p. 146).

However, it should be emphasised that the presented interpretation of the provision contained in can. 1791 § 1 CIC/17 was not unanimously accepted by all representatives of jurisprudence and ecclesiastical jurisprudence. Polish canonist Jerzy Grzywacz, in discussing the issue in question, cited the views of researchers and rotal judgments that did not always harmonise with the line taken by the legislator on this matter. The possibility of exceptional departure from the provision contained in can. 1791 § 1 CIC/17 was explained by the fact that the established norm was not an end in itself. It was argued that the principle of testis unus testis nullus applied when the judge, apart from the lack of other evidence that could replace witness evidence, also had no other supplementary circumstances and auxiliary means at his disposal (Grzywacz 1985, pp. 35–36). These, admittedly, while not constituting full evidence in themselves, could, in conjunction with the testimony of a single witness, provide the adjudicating judge in a particular case with an effective means of ascertaining the truth (Pinto 2001, p. 908).

On the other hand, it should be emphasised that the mere fact that the judge had two or three consistent and credible testimonies in the case did not definitively determine its outcome and the passing of a sentence. The construction in question was not applied automatically and did not completely exclude the judge’s activity in assessing the value of evidence and seeking the truth.13 According to the provision contained in can. 1791 § 2 CIC/17, the legislator allowed the court, in certain cases, a degree of discretionary authority. For example, if a judge had doubts despite having the evidence of two sworn, consistent, and truthful testimonies, he could, in accordance with the law, request more complete evidence.14 It is worth mentioning that, apart from one exception indicated in can. 1791 § 1–2 CIC/17 concerning a qualified witness testifying about matters performed ex officio, the legislator mentioned in other places of the code specific clergy whose individual testimony was also honoured. For example, the testimony of the Bishop of Rome was given full evidentiary value because of his authority and position within the structure of the Catholic Church (Vermeersch and Creusen 1946, pp. 86–87). A similar privilege was applied to cardinals, recognising their individual testimony regarding papal statements as credible and important.15 It seems that this was analogous to the solutions used in pre-code law, in which testimony given by the highest secular authorities, such as an emperor or king, also had the undeniable value of a complete proof (Myrcha 1936, p. 152).

In contrast to the solutions adopted in the 1917 Code, which explicitly articulated the numerical criterion for witnesses, the issue of the oath, and the consistency and credibility of testimonies, the legislator in the currently binding Code for the Latin Church abandoned this approach. Moving away from a direct enumeration of the characteristics of valid and effective witness evidence, the focus was primarily placed on the assessment of the evidentiary weight of a single witness’s testimony. According to can. 1573 CIC/83, it was established that the testimony of a single witness cannot have full evidentiary force, unless it concerns a qualified witness who testifies about matters occurring in connection with the exercise of office, or unless factual and personal circumstances indicate otherwise.16

It seems that the wording of the first part of the canon constitutes an expressis verbis reference to the ancient procedural rule prohibiting the acceptance of a single testimony (Rozkrut 2015, pp. 109–10). The legislator therefore indicated a general negative rule that the testimony of a single witness does not constitute full evidentiary value, while at the same time listing two exceptions to this rule (Adamczewski 2023, pp. 9–22). Testimonium unum was given full evidentiary value, but only in clearly defined cases. The first related to the substantive aspect. It concerned the testimony of a qualified witness testifying about acts performed in an official capacity (Pinto 2001, p. 908). A similar provision was adopted in the previous code, which specified that individual qualified testimonies had to be related to the public function performed by the witness (Conde 2006, p. 464). The second circumstance constituted an exception of a substantive nature and was referred to as rerum et personarum adiuncta (Ramos 1998, pp. 358–59). The essence of the second exception was that the judge granted full evidentiary value to the testimony of a single ordinary witness if this resulted from a positive analysis of the circumstances of the case or the persons involved. This was a new solution in the normative sense, although it had been known and practised to some extent in the field of jurisprudence for a long time (Chiappetta 1988, p. 664).

A similarly worded canon stipulating the insufficiency of a single testimony was also adopted in the 1990 Code of Canons of the Eastern Churches,17 which was promulgated by Pope John Paul II by virtue of the Apostolic Constitution Sacri canones.18 The section regulating the assessment of witness testimonies clearly articulates the insufficiency of a single testimony. In accordance with canon 1254 of the CCEO, it has been established that:

The testimony of a single witness cannot be considered full proof, unless it is a qualified witness who testifies about matters performed in an official capacity, or the circumstances of the case or persons suggest otherwise.19

The articulated rule formally applied as a general norm. It was included in an important section of the code containing the canons regulating the contentious process.

It should also be emphasised that the legislator’s intention was that, with the promulgation of the code, the legislative authorities of the individual Eastern Churches would adopt their own specific norms, harmonising with their disciplinary tradition and the guidelines of the Second Vatican Council. Undoubtedly, the code was a unique work that realised the centuries-old and complex legal thought of the Eastern Catholic Churches (Adamowicz 1998, pp. 118–19). In this context, it is worth noting that the cited canon 1254 of the CCEO, regulating the obligation to observe the principle of testis unus testis nullus, was formulated in almost the same way as in the 1983 Code of Canon Law.

4. The Positive Aspect of the Principle of Testis Unus Testis Nullus in Ordinary Canonical Proceedings

The provisions of canon law governing the conduct of ordinary contentious proceedings contain general norms (leges generales) which, as a rule, should be applied analogously to all special proceedings before ecclesiastical courts. As lex suppletiva, they constitute a kind of essential model and binding point of reference for the aforementioned proceedings, with due regard for their own special norms (leges speciales) (Chiappetta 1988, p. 618). For this reason, the requirement of double testimony contained in the section of the code regulating ordinary contentious proceedings has the value of a general norm. It should therefore also be applied, as a rule, in other canonical matters and special proceedings.20 According to can. 1573 CIC/83, the testimony of a single witness cannot constitute full proof. The legislator established that it is insufficient, thereby providing the judge with a specific guideline for assessing the evidentiary value of witness testimony. (Conde 2006, pp. 463–64).

In the doctrine of canon law, it was rightly pointed out that a negatively formulated principle under applicable law could be interpreted positively in connection with the content of the former can. 1781 § 2 CIC/17, which stated that the testimony of at least two or three sworn, consistent and credible witnesses was full and sufficient evidence. The admissibility and effectiveness of witness testimony ultimately depended on several conditions being met. The catalogue of necessary elements consisted of: the credibility and consistency of the testimony, an adequate number of ex visu witnesses, and the oath taken by them (Lombardia and Arrieta 1987, pp. 1139–40). Although the content of the aforementioned provision, expressed in positive terms, has not been repeated identically in the current code, it is reasonably assumed that it continues to apply, and its logical consequence is can. 1573 of the Code of Canon Law/83 (Sztychmiler 2007, p. 228).

By establishing the aforementioned procedural rule, based on natural justice, the ecclesiastical legislator thus imposed a series of requirements that testimony given in court should meet. Above all, it was mandated that such testimony possess credibility (Myrcha 1936, p. 154). Consequently, witnesses were obliged to fulfil the legal duty of speaking the truth.21 This requirement was not met if specific reasonable objections were raised during the trial against the witness or his testimony, or the manner in which it was presented, or if reasonable doubts arose. These could, for example, concern the witness’s unsuitability or incapacity, or be related to the witness’s behaviour, which was uncertain, unstable or inconsistent in the presentation of their testimony (Ramos 1998, pp. 357–58).

Another important element was the consistency of the testimonies. This requirement was met if the testimonies were not essentially contradictory. They had to be consistent and relatively uniform. It was obvious that differences in secondary issues did not affect the value of the testimony. On the contrary, sometimes they even made them more credible. Consistency of testimony even in the smallest details, especially with regard to past and distant facts, could usually be a sign of bias or collusion between the witnesses, or even that they had been bribed (Karłowski 1964, pp. 392–93). The most glaring and, at the same time, worthless form of inconsistency in testimony was contradiction. This occurred when witnesses made contradictory statements about the same and only fact, such that both could not be true at the same time (Fąka 1978, p. 195). The requirement of consistency was met if the witnesses were unanimous and testified without apparent discrepancies (Del Amo 2023, pp. 963–64). It was important that they testified based on their own knowledge. In particular, what they personally and directly saw or heard was valuable. As a result, ex auditu testimony and testimony based only on personal opinion or conjecture had weaker evidentiary value. (Sztychmiler 2007, p. 199).

The third element constituting full evidence from witness testimony was the oath, which the legislator linked to the obligation to tell the truth.22 This was especially true in matters of public interest (Del Amo 2023, p. 959). The oath taken by a witness in court was a promise to tell the truth. This had significant consequences, especially for believers, as the person taking the oath invoked God himself as a witness. The introduction of a religious element into the solemn obligation of a witness to tell the truth meant that if they evaded or directly failed to fulfil this obligation, they exposed themselves to legal and moral responsibility. Lying or deliberately concealing the truth meant that their act constituted a sin and at the same time fulfilled the criteria of the canonical offence of perjury. The oath was therefore a means of spiritually mobilising the parties and witnesses to testify truthfully (Pawluk 1990, p. 250).

The key element of the admissibility and full value of oral evidence in the context of the rule under analysis was the number of persons giving it. Complete evidence consisted of consistent, credible and sworn testimony given by at least two witnesses. Having this type of evidence at their disposal not only gave the judge the legitimacy to pass judgement, but also, in connection with certain elements of the principle of legal evaluation of evidence, imposed such an obligation on them (Lombardia and Arrieta 1987, p. 1140). A larger number of witnesses significantly reduced the risk of various false machinations. On the basis of several testimonies, taking into account the circumstances accompanying their submission, it was easier for the judge to discover inconsistencies between the testimonies and the objective state of affairs than in a situation where he had only one witness, even if that witness was trustworthy and highly respected (Myrcha 1936, pp. 146–48). It should be borne in mind that one of the main purposes of the application of testis unus testis nullus in canonical proceedings was to make it easier for the judge to reach an internal conviction and moral certainty on the matter being decided, and thus to remove internal uncertainty or even pangs of conscience (Chiappetta 1988, p. 664). Alfons Myrcha, an eminent canonist, aptly wrote in his reflections on the role of procedural requirements and their legitimacy:

The above principle, adopted by ecclesiastical legislation and applied to all criminal and contentious cases, is justified by everyday experience and natural justice (in aequitate naturali). Nevertheless, it is unlikely that truthful witnesses, fully aware of the sanctity of the oath and the obligation to tell the truth, would consciously and deliberately give false testimony and thus commit the crime of perjury (Myrcha 1936, p. 156).

5. The Negative Aspect of the Principle of Testis Unus Testis Nullus in Ordinary Canonical Proceedings

Manuel Arroba Conde argued that the Roman rule testis unus testis nullus, which was applied to the procedural law of the Church, was a classic example of a legal and negative evidentiary construct. In canonical proceedings, where the principle of free evaluation of evidence generally applied, it was a kind of exemplum confirming certain deviations in favour of legal evaluation of evidence (Conde 2006, pp. 463–64).

The purpose of adopting such a statutory solution regarding the assessment of the value of personal evidence was certainly to ensure maximum justice in canonical proceedings. It was reasonably argued that a judge’s ruling based solely on a single testimony posed a serious risk of violating the principle of justice. However, when several witness statements were available, or even a single statement but in conjunction with other means of evidence, this risk was significantly reduced (Fąka 1978, pp. 195–96). In addition, relying solely on the testimony of a single witness increased the real risk of judicial abuse, especially in the form of slander, bribery, and even revenge. As a consequence, this could easily lead to unfair verdicts (Milotić 2019, pp. 856–57). Apart from the phenomenon of perjury, it was rightly pointed out that the prohibition of testimonium unum was also a form of protection against witnesses who acted under a misguided perception of reality. In other words, the aim was to eliminate witnesses who were in the wrong and may not even have been aware of this fact (Fąka 1978, p. 196). The judge’s ruling based solely on one testimony significantly limited his ability to arrive at the truth. He could not even conduct a simple confrontation with other people regarding what he had heard from the sole witness (Bettetini 2019, pp. 53–54). Therefore, assessing the credibility of the testimony was significantly impeded. The situation would be different if the court had other evidence at its disposal. Even with only one testimony, it could more easily obtain objective confirmation or refutation of the facts presented by a single witness based on other evidence (Pawluk 1990, p. 247). On the other hand, it was rightly pointed out that a large number of witnesses did not always guarantee the credibility and reliability of testimony. An excessive number of witnesses could sometimes even have a destructive effect on the course of the trial. This was particularly true when witnesses were presented by the parties without reasonable grounds or when they acted in concert with the intention of deliberately misleading the judicial authorities (Fąka 1978, p. 198). Anticipating this kind of danger, the legislator gave the judge the right to limit the excessive number of witnesses in a case.23 He could reduce the number of witnesses, but only if he was convinced that subsequent witnesses would not contribute anything new and constructive to the case or that the evidence gathered in the case was sufficient to reach a decision. Any reduction in the number of witnesses could not be made to the detriment of the case, and at the same time should prevent any protracted proceedings and ensure their efficient conduct (Sztychmiler 2007, pp. 207–8).

Nevertheless, while imposing binding requirements on judges with regard to the assessment of evidence, the legislator did not abandon the idea of leaving them a certain degree of freedom in this area. It recognised that the activity, experience and personal conviction of the court are invaluable in obtaining evidence and reaching a decision that is consistent with the truth (Chiappetta 1988, p. 664). Therefore, if the evidence from the testimony of two or three witnesses, although it met all other required elements, raised doubts in the judge’s mind or did not constitute a sufficiently solid basis for a decision, the judge could order that it be further supplemented; for example, by requesting the summoning of new witnesses or the acquisition of other evidence (Sztychmiler 2007, p. 158). However, if the judge had only one statement from an ordinary witness, taken in isolation from all other evidence, it was still recommended to adopt a cautious and prudent approach. Warnings were issued against too hastily dismissing the value of a single testimony (Pinto 2001, p. 908). It was rightly pointed out that in such cases, the judge should endeavour to supplement the incomplete evidence with other means, such as circumstantial evidence. If this was performed effectively and the judge became internally convinced of the truth of the facts being proven, he or she was then entitled to pass judgement in the case (Lombardia and Arrieta 1987, p. 1140).

In conclusion, it is worth noting that the code provides for the possibility of authenticating certain events on the basis of a single ordinary testimony, which is confirmed in broadly understood canonical proceedings.24 This applies, for example, to situations where it is necessary to prove that a sacrament or one of the sacramentals has been administered. This is assuming that there is no authentic document confirming the event in question and that no harm will come to third parties as a result (Chiappetta 1986, p. 1118).

6. Conclusions

In the canonical process, which constituted the implementation of substantive law and the realisation of justice, an important task was also to arrive at the truth. Evidence played an indispensable role in achieving this goal. Among these, witness testimony has always played a significant role. In the canonical legal tradition, inspired by biblical sources and Roman law, it was accepted from the very beginning that the testimony of a single witness could not, as a rule, constitute full evidence. For this reason, the rule testis unus testis nullus has always been an important point of reference for legislators and has been the subject of keen interest. For this reason, it was included in the canonical sources of the code in the section regulating ordinary contentious proceedings, both in the Pio-Benedictine Code and in the currently applicable Code of Canon Law and the Code of Canons of the Eastern Churches. It seems that its similar placement in the structure of these legal acts was intended to emphasise its universality and significance. The general provisions (leges generales) regulating ordinary contentious proceedings, including the rule on witnesses, were an important subsidiary source for canonical special proceedings.

It is noteworthy that although the Roman principle of witnesses had been a very important reference point in canonical legal tradition for centuries, the Church did not apply it in a formalistic manner and allowed for deviations in its application. It is worth underscoring that this practice was not entirely consistent with the legislative and jurisprudential line shaped in the biblical25 and Roman sources, especially since the proclamation of Constantine the Great’s imperial constitution of 334.26 Both of these systems adopted a strict requirement of two or three witnesses in a case, with no possibility of exceptions.

In canonical practice and in the sources of the code governing the ordinary canonical process, the testimony of a single witness did not in itself constitute full proof, but neither could it be considered in advance to be devoid of any value. Two exceptions were provided for.27 The first concerned a qualified witness. The second exception was defined as rerum et personarum adiuncta. It was a relatively broad formula that gave the judge greater discretion in considering the specific case of a sole witness.

It is possible that the Church assumed that the application of normative exceptions to the rule of two witnesses would not pose a threat to the achievement of fundamental procedural objectives, such as respect for the procedural guarantees of the parties, preventing false accusations from being easily brought to court, and arriving at the truth in the trial and guaranteeing a fair trial. It is clear that direct inspiration in this matter was drawn from Roman law, which, as insigne veteris sapientiae monumentum, was an invaluable legal reference for the Church, especially in matters of procedure and evidence. With regard to the procedural rule under analysis and exceptions to its application in canon law, two imperial constitutions cited above served as models. The first, from 333, regulated the issue of audientia episcopalis and the problem of testimonium episcopi unum. It is worth remembering that this law opened a collection of several religious constitutions granted by the emperor specifically for the Church. The second constitution, from 334, established the universal requirement of double testimony.

It is very plausible that the two imperial laws issued by Constantine the Great in close succession, seemingly contradictory in terms of the number of witnesses, were a deliberate move on his part. The ruler could order an exception to the generally applicable law, especially when considering the broader context of his political activity and its goals, the implementation of which he linked to the involvement and even exploitation of the Church. Moreover, the emperor’s absolute power, the essence of which is well reflected in the well-known paremia quod principi placiut legis habet vigorem,28 provided him with unlimited possibilities in the legislative field as well. In this context, an interesting and meaningful connection emerges between the imperial regulations mentioned above and the centuries-old and impressively vibrant canonical tradition, which respects the requirement of testis unus testis nullus, but does so in a flexible manner, allowing for exceptions.