The Search of St. Peter’s Memory ad catacumbas in the Cemeterial Area ad Duos Lauros in Rome

The purpose of our study is to research Peter’s memory ad catacumbas. According to the Depositio Martyrum—a document of the late Emperor Constantine period—there was no memory of the first St. Peter’s Basilica on the Vatican Hill. We start with a critical analysis on the Roman Basilica attributed to Emperor Constantine in Liber Pontificalis, then we deepen the search of Peter’s memory in the catacombs of the Sts. Marcellinus and Peter (ad Duos Lauros), also known as Tor Pignattara. Indeed, the basilica and mausoleum built in this cemeterial area are the only buildings attributable, with certainty, to Emperor Constantine, who wished to be buried in the mausoleum, close to an apostle. Besides some striking archeological finds on Peter’s memory already discovered near a particular cubicle in these catacombs, a geometrical and mathematical study of the unusual architectonic characteristics of the basilica and mausoleum of Tor Pignattara shows that the buildings were part of a single architectonic plan, very likely designed for coding data useful to locate Peter’s burial site unambiguously, in the area of the cubicle mentioned.


Introduction
Since the IV century the Catholic Church venerates Peter's memory in the Vatican. This memory was confirmed about 80 years ago, in an excavation campaign, when the archeologists A. Ferrua, B. M. Apollonj Ghetti, E. Josi, and E. Kirschbaum found, just beneath the altar in St Peter's Basilica, a little monument of the II century, which recalled Peter [1]. The monument is a small aedicule, the "trophy" mentioned in a letter of a Roman priest Gaius -at the time of Pope Zephyrinus (199-217) -, who, arguing with someone who claimed to have the tomb of St Philip in Hierapolis, Asia Minor, answers: «I can show the trophies of the Apostles; in fact, if you go to the Vatican hill, or to Via Ostiensis, you will find the trophies of those who founded this Church» (Eusebius of Caesarea, Historia Ecclesiae, 2.25, 5-7). The discovery was important because the niche had remained at the center of the Basilica of the IV century, and later in the actual St Peter's Basilica. Nevertheless, this discovery is one of the most controversial of the XX century.
The discovery concerns the tomb, not Peter's remains. The four archeologists concluded they had found the site of Peter's burial, or at least one of the sites of his burial, because they had not found human remains attributable at the apostle [1]. But a sudden and unexpected fact occurred in the 1960s. After several years, investigating Christian graffiti in the area of Peter's tomb, the epigraphist M. Guarducci, who had not participated in the excavations campaign, announced she had identified To explain this ancient St Peter's memory, it was also suggested that the catacombs in Via Ostiensis have received, for a certain period, both Peter's and Paul's remains, but the archeological evidence seems to exclude this hypothesis [15]. In St Sebastian's catacombs there is only a trace of the refrigeria in honor of SS Peter and Paul, in other words, of the funerary rituals, very popular, carried out every year on June 29 (both saints are still today celebrated by the Catholic Church on this day).
This should be the origin of the Memoria Apostolorum in St Sebastian's catacombs, i.e., a funerary ritual very likely established around the year 258, according to the date of the consuls Tusco and Basso mentioned in the Depositio martyrum [15]. Conversely, the contemporaneous presence of the remains of the two apostles in St Sebastian's catacombs is a vexata quaestio [16, p. 67], because the only indirect proof of this presence -during the persecutions of Emperor Valerianus -traces back to medieval epigraphic collections of a poem of Pope Damasus, dedicated to the two apostles, now lost [17].
Moreover, the archeological excavations have not confirmed the presence of remains and burials attributable to SS Peter and Paul [18]. Thus, the many graffiti dedicated to SS Peter and Paul, found in the cemeterial area of St Sebastian's catacombs, can be explained by the funerary ritual previously mentioned.
In the years 1948-1949, to solve the enigma of St Peter's tomb, at the end of the excavation campaign in the Vatican caves, because no traces of St Peter's relics had been found, some important personalities of the Vatican approached even an Italian mystic, Maria Valtorta, in the attempt to get some supplementary information about the site of Peter's remains [19].
The purpose of our study is to research St Peter's memory ad catacumbas, in the catacombs of Rome [20]. In other words, we look for the last catacomb that has housed, or may still house today, St Peter's remains.

We start first with a critical analysis of what is reported in the Liber Pontificalis on the Roman
Basilicae attributed to Emperor Constantine (Section 2), because very likely he built one of them very close to the site where St Peter's memory and remains were located. Following this trace, we then deepen the search of St Peter's memory in the catacombs of the SS Marcellino and Pietro 1 in the suburbs of Rome -known today as Tor Pignattara (in the ancient Via Labicana) -, because its Basilica and Mausoleum are the only buildings attributable with certainty to Emperor Constantine (Sections 3, 4 and 5). In Section 6, a geometrical and mathematical study of the unusual architectonic characteristics of the Basilica and Mausoleum of Tor Pignattara shows that the buildings were part of a single architectonic plan, very likely designed for communicating important data on Peter's burial site; at least this is our conjecture. The mathematical analysis supports the hypothesis that St Peter's memory ad catacumbas refers to this cemetery. Finally, in Section 7 we summarize the main findings and draw some conclusions, which may lead archaeologists to validate, with excavation campaigns, our findings and conjecture.

The Roman Basilicae attributed to Emperor Constantine in the Liber Pontificalis
The only written source concerning the Constantinian Basilicae built in Rome is the Liber Pontificalis (Book of popes), an editorial compilation which dates back to the VI century [14, p. 325].
According to the interpretation commonly accepted by scholars -already supported by Duchesne, XIX century editor of Liber Pontificalis, and lately by other scholars as Krautheimer [21] -the editors of the Liber Pontificalis transcribed archival documents belonging to a historical period prior to several centuries [14, p. 329 Therefore, let us start summarizing the information given by the Liber Pontificalis (LP) about the Constantinian Basilicae, by considering the most recent historical studies. Then, in the following section, we study the planimetry of the Basilica and Mausoleum complex erected in the cemeterial of SS Marcellino and Pietro, in the ancient Via Labicana (Tor Pignattara), built with certainty by Constantine. In fact, as we will see, this complex seems to play a fundamental role in finding the memory of St Peter ad Catacumbas.
The Liber Pontificalis is a collection of biographies of popes, written in Rome since the beginning of the VI century. The first 33 biographies are synthetic. The 34-th biography, dedicated to Sylvester I, pope in the years 314-335 and contemporary of Constantine, is quite detailed.
In Figure 2 we show, schematically the location of the Roman Basilicae allegedly built by Constantine in Rome, with reference to the Aurelian Walls and the consular roads close to them [23].   [16][17][18][19][20], erected on the Vatican Hill ( Figure 2). Besides the Liber Pontificalis, other sources useful for deciding whether the Basilica was really built by Constantine, or by his son, are three epigraphs, today lost [14, p. 338]. But the historical reliability of this epigraphic evidence is not uniquely accepted. To clarify this point, Barbero analyzes the inscription in the mosaic of the apse: «Seat of justice, house of faith, palace of chasteness / is this you see, all pervaded of mercy, / which is glad of the sublime virtue of the father and of the son / and makes equal his author to the fame of the parent» [14, p. 339]. 2 The inscription seems to affirm that the author of the Basilica praises himself, just because of this construction, to be equal to his parent, who might have been either Constantine or Costanzo I (Constantine' father).
Barbero, on this point, comments that the glory of Constantine already in 312 was immensely greater that his father's glory, and that it is not possible to imagine that a mature man of such a large success would have shared it with his father. Moreover, this behavior would have been against the image of himself that Constantine wanted to establish. On the other side, it is known that his sons were very interested in affirming that they had equaled their father's glory [14, p. 340   . This is the conclusion largely shared by scholars and archeologists, because of the masonry used and a coin found in the lime of the Basilica, which allow to date the Basilica as a true Constantinian one [14, pp. 344-346]. Basilica [22, p. 41]. According to tradition, during the persecutions of Valerian, in the III century, the remains of SS Peter and Paul were hidden in the catacombs of the area and there revered for about 50 years. However, in the years, the veneration of St Sebastian prevailed in naming the cemetery and the Basilica after him, very likely because remains of the apostles were never buried there, as confirmed by archeological excavations. [18].
In synthesis, the only Basilica that, with certainty, can be attributed to Constantine is that erected in the area today known as the catacombs of SS Marcellino and Pietro (Tor Pignattara). Moreover, just attached to the Basilica, Constantine erected the Mausoleum for burying his mortal remains.
However, according to tradition, only the remains of his mother Helena were buried there.
However, even admitting the desire of revenge, the necropolis of the Equites Singulares would have been, in any case, destroyed for erecting the Basilica, built -according to Guyon [29], [23, p. 89] -with exact correspondence with some perimetric walls of the cemetery of the Equites Singulares.
According to Deichmann and Tschira, the Basilica was erected before the Mausoleum, in the years Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 1 February 2021 320-325, and the Mausoleum was outside the cemetery of the Equites Singulares [28, p. 64], even though the unity of the complex cannot be excluded [23, p. 167]. The Mausoleum could have been built in occasion of the twentieth year of Constantine's reign (Vicennalia), in 326 [18, pp. 45-46], [22, p. 44]. However, as noticed by Barbero [14], the hypothesis put forward to explain the anomaly of this complex is not shared by all scholars and it is disclaimed by the fact that the cemetery of the Equites Singulares Augusti, according to many archeological finds, should have been located in the area but not below the Basilica and Mausoleum. If the cemetery were below the Basilica and Mausoleum, then Constantine would have committed an act of blasphemy, without precedents in Rome, which is out of question [14, p. 334]. Therefore, this unacceptable hypothesis is more an ad-hoc explanation formulated to explain the evident asymmetry, in a world of architectonic order, otherwise inexplicable.

The eponymy of the catacombs of the SS Marcellino and Pietro
The cemetery of SS Marcellino and Pietro was located close to the ancient Via Labicana ( Figure   2), to the North -now near Via Casilina -, which originally started at Porta Esquilina, where the Arch of Gallieno is now located, at the Servian Walls, not shown in Figure 2. It is at about two Roman miles (about 3 km) away from the Aurelian Walls, built in the III century. These catacombs aroused archeological interest towards the end of the XIX century [33][34], but had been partially explored more than a century before by A. Bosio [34]. The catacombs extend in a vast area of about 3 hectares, with at least 5 km of galleries deployed in two levels [36].
Originally, the cemetery was named ad Duas Lauros (at the two laurels) and, after Constantine, ad St Helenam, for the presence of the grand Mausoleum, whose ruins are still visible. The area was also referred to as sub Augusta and in Comitatu, because of a close imperial villa belonging to Constantine.
The medieval itineraries recall several groups of martyrs buried in the cemetery: besides Marcellinus and Peter, also Tiburzius, Gorgonius, the Four Crowned (Quattro Coronati), a group of several tens of martyrs killed during Diocletian's persecutions.
Marcellinus, a priest and Petrus, a laic and exorcist, were martyred at the beginning of the IV century in Via Cornelia, in the locality known as Sylvia Nigra and after their death called Sylva Candida. Pope Damasus learnt the details of their death directly from their executioner, as he wrote in the ode dedicated to their memory and laid down in the crypt. The ode is lost but its content is known [33, p. 261]. It starts as: «Marcelline tuos pariter Petre nosce triumphos. Percussor retulit Damaso mihi cum puer essem…», that is: «Marcellinus, and equally you Petrus, be proud of your trophies [e.g.
their deaths]. The man who hit you with the sword told me, Damasus, when I was a kid…». Let us note the "obvious" order of the names: first Marcellinus, because he was a priest, then Petrus, a laic, because less important in ecclesiastic hierarchy.
From the Acts of their martyrdom [33, p. 261] we know that their bodies were buried near the body of St Tiburzius. However, even if there are so many martyrs in this cemetery, the area is known as the catacombs of SS Marcellino and Pietro. Because many catacombs were excavated before their death, the cemetery could have been named and dedicated to someone else.
In the medieval Itineraries, which guided the pilgrims visiting the principal sites of Christian martyrs in Rome, we do find the indication of the two martyrs, but with the order of their names  In the next section we bring striking evidence that supports our hypothesis, and in Section 6 we show that the architects and engineers of the complex Basilica plus Mausoleum, erected simultaneously in the cemeterial area ad Duos Lauros, might have coded in it the information necessary to locate a precise position, within the cemeterial area, where Peter's remains might have been hidden and might be still today.

The memory of St Peter apostle in the catacombs of SS Marcellino and Pietro
In this section we summarize what the archeologists have found regarding St Peter's memory in the catacombs of SS Marcellino and Pietro.
The first finding is a striking sepulchral epigraph ( Figure 5) that may refer to Peter's burial, but  Therefore, just a single letter of the epigraph is bigger that the entire graffiti shown in Figure 1. If that simple graffiti has been considered as the indirect proof of Peter's burial in St Peter's Basilica on the Vatican Hill, then it cannot be excluded that the plaque of Figure 5 can be a proof that St Peter, maybe for a certain period, was buried in the catacomb ad Duos Lauros.

Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 1 February 2021
The epigraph was found in 1912 in a cubicle of the region known as "delle agapi" (of agapes), in  Figure   5 had not yet been found.
Marucchi has also tried to explain the unexpected presence of the epigraph of Figure 5  who thought he had found the crypt of the two martyrs to whom the cemetery was dedicated [35].
After another period of oblivion, in 1852 it was the turn of G. B. De Rossi to explore these catacombs and only in 1897 the PCAS started an excavation campaign [33, p. 263].
The excavation was complicated by the fact that in the planimetry of underground Rome according to Bosio (1632), map edited by G. Berti e F. Contini [35], some cubicles were indicated as accessible, but they were not so in 1900 [47]. In fact, J. Wilpert, who just in those same years was excavating some cubicles already visited by Bosio but later lost, clarified that when the paintings of a room had been copied by Bosio's drawers, that room was filled again with dirt, so that already G. Peter's depositio was found out of place [43, p. 60], in a cubicle of the area "of the agapes", corresponding to the quadrant B7 -area colored in blue -of the map shown in Figure 6. The numbers given to the cubicles with frescoes was done before the 1971 edition of the book by A. Nestori, later published in an expanded edition [49]. Since 1971, by convention, Nestori's numeration has been followed, also in the map by Deckers [31], shown in Figure 6.
Of the many cubicles reported in Figure 6, the most important seems to be cubicle no. 58 -red area in Figure 6-, located just a little North of the region where the epigraph was found. In this cubicle there is a fresco depicting St Peter holding a scroll. Figure 7 (panels a and b) shows a watercolor of this fresco, published by J. Wilpert [50], which he attributes to the "the Prince of the Apostles" and to the second half the III century. The comparison with the black and white photograph (panel c of Figure 7) shows the accuracy and precision of the artist, C. Tabanelli 6 , who copied it.
In conclusion, the North-West region close to cubicle no. 58 shows significant traces of the presence of St Peter's memories, therefore, in the next section, we search the precise area where his remains might have been buried for a period, or, maybe, might still be. where St Peter's fresco was found. Source of the original planimetry: [31].

The area where St Peter's remains might have been buried and might still be
Following the discussion of the previous sections, it is obvious to search the alleged crypt of St Peter near the cubicle no. 58. To find the area of the site where St Peter's remains were likely buried and, perhaps, might still be, we explore some interesting geometrical relationships, worth of note, in the planimetry of the area, first in general terms, secondly with some mathematical calculations. Both approaches lead to a very restricted area near the cubicle 58.

Geometrical relationships deducible from the planimetry
Besides the different orientation of the narthex and the Basilica already evidenced in Figure 3, another striking fact to notice is that the tangent line to the Mausoleum, conducted along the short side of the narthex, crosses exactly the cubicle 58, as shown in Figure 8. The planimetry is now rotated 90° counterclockwise for later allowing the comparison with a map by Bosio [35]; the angle, termed Of course, the crossing of cubicle 58 might occur just for chance, but we can notice that the only important gallery with this same direction, found in the whole catacombs area, is the Gallery of the Four Crowned (Quattro Coronati, dashed red line), Figure 8. Now the cubicle 58 has its entrance at 90° with this gallery, therefore this cubicle has its entrance side parallel to the short sides of the narthex. Moreover, it is possible to identify in Figure 3 an inner semi-circle in the apse of the Basilica, indicated with the dashed blue line in Figure 9, besides the outer (continuous blue line) semi-circle of the apse. In Figure 9 we have traced the full circles to show that the outer circumference of the apse is about equal to the outer circumference of the Mausoleum.
At this point, in Figure 9 we can notice another relevant "coincidence": the line tangent to the two inner circles (Mausoleum, apse, green line) is parallel to the line tangent to the outer circle of the Mausoleum and short side of the narthex (red line), evidently not by chance. Both are inclined by the angle = 4°. In other words, it seems that the Mausoleum and Basilica complex was planned and built following a single plan. Now we verify, mathematically, our conjecture.

Mathematical calculations lead to a very restricted area near the cubicle 58
Let us refer to a Cartesian orthogonal coordinates system, with the origin at the center of the Mausoleum, point 1 in Figure 9. The center of the semi-circles of the apse is at 2 with coordinates in pixels (22; 794), with the minimum precision of 1 pixel. The size of Figure 9, in pixels, is .
The radius of the semi-circle of the apse, dashed blue curve in Figure 9, not given in [32], can be accurately computed from Figure   In Figure 11 we have drawn line 4 , specular of line 2 , parallel to line 3 and tangent to the inner circle of the Mausoleum, North side. We show now that lines 1 e 4 intersect at the cubicle 58 (see point 1 in Figure 12), and lines 2 e 3 intersect at point 2 .
The distance along the − axis is the same of 1 (i.e., cubicle 58) while that along the − axis, , is moved to the right of the difference of the radii of the Mausoleum − =

Many unexplored cubicles and galleries
According to the results of the previous sections, the intersection 2 between lines 2 and 3 falls within an area apparently without cubicles ( Figure 12). However, we must remember that in that area the catacombs are deployed in two levels, with the lowest (second) level drawn with gray dots in Figure 12. As indicated by the red arrow, in the second level there are galleries not completely explored by Bosio [35], because so they appear in his map, and still as unexplored galleries are also reported in the maps of the PCAS archive [31] that we have used to draw Figure 12. To better appreciate the details, Figure 13 shows Bosio's map [35] corresponding to the same region of that shown in Figure 12, with the same orientation of Figure 12 Figure 11. The red arrow indicates an interrupted gallery, which is at the second level of the catacombs, not yet completely explored. This gallery falls very close to the cubicle 58 and the Gallery of the Four Crowned, but it should indicate a site at a lower level. Figure 13. Detail of the planimetry drawn by A. Bosio [35] of the same area and orientation of Figure   12, upper right side. Bosio's cubicle no. 47 corresponds to Nestori's cubicle no. 57 of Figure 12 [49, p. 69]. This cubicle is encountered just after cubicle 58 along the direction of the − axis.
Moreover, in the most recent maps of the PCAS archive, the second level of the catacombs is not even drawn, as it can be noticed in Figure 1 of a very recent paper concerning the catacombs of SS Marcellino and Pietro [51, p. 1024], whose details concerning the cubicle 58 and Quattro Coronati are reported in Figure 14. In this Figure, the path that today visitors can walk (in red) goes through the Galleria dei Quattro Coronati and the region of "the Agapes". The first level of the catacombs is drawn in black, the second in yellow. In this published map [51], below the cubicle 58, which is visitable and presents an ambient connected to the left -marked as an arcosolium (an arched niche), not reported in the map published in [31] (Figure 12) 40 years earlier -, no second level is indicated, as it can be noticed by comparing Figures 13 and 14. The first underground level of the catacombs is drawn in black, the second level in yellow. Now, if our conjecture is plausible, the question that arises is how the Roman architects and engineers of the time (beginning of IV century) could be so precise. They had to plan the length of the radii of the Mausoleum and apse in such a precise relation to make lines 1 and 4 intersect in 1 and lines 2 and 3 intersect in 2 , therefore referring the angle = 4° to an underground site, e.g. the cubicle 58, obviously not visible.
It is well known that Roman engineers were able to build very long aqueducts with very small slopes [52], down to 8 cm per 1 km, i.e. inclined of an average angle = arctan(0.08 1000 ⁄ ) ≈ 0.00008 rad = 0.0046°. If they were able to manage such a small angle, although with the help of gravity [53], they might as well managed angles 3 orders of magnitude larger.
As for the "visibility" of the cubicle 58 or the interrupted galleries close to it, Bosio himself seems to provide the solution devised by the Roman architects and engineers working in the cemeterial area [35]. Notice, in fact, that in correspondence of number 28, see Figure 13, there is a black square dot with an "×" on it. Bosio writes that he had found «openings, or narrow openings, which coincided on the surface [with galleries or cubicles underground], but now filled» [35]. These narrow openings were usually built for providing air circulation and light, down to many levels (ventilation and light shafts, lucernaria and luminaria), and could also be used, of course, to sign, with a post, the presence opening open from which it is possible to climb to other cubicles and cemeterial roads of the superior level, indicated with dots» [34]. In other words, the cubicle explored by Bosio was in the second level and it allowed to pass from the second level to the first level not by a stairway but by a hole in the ceiling, just near 2 , that is, near the tunnel interrupted indicated by the red arrow in Figure 12. As noticed, his cubicle 48 has no correspondence in the modern maps [49], thus indicating a possible error by Bosio or a cubicle not yet found by more recent explorations. Now, we know for certain that in the second level there should be the crypt of the martyr Gorgonius, but this crypt has not yet been found because the second level has not been fully explored [11, p. 238]. The Salzburg Itinerary, reported in the second line of  Figure 11), then the crypt of Gorgonius should have been found long ago because this area has been completely explored. On the other hand, quite different is the situation for the second level in the area to the North of the Galleria dei Quattro Coronati, in the upright side of Figure 14.  [12]. Therefore, it is possible that also Peter apostle and Marcellinus martyr were moved to the most ancient nucleus of the catacombs, and in the lowest level, hidden in anonymity to avoid profanation.
According to our reconstruction and conjecture concerning the design of the Mausoleum and Basilica complex in the catacombs of SS Marcellino and Pietro, the Roman Christians, and also It must be recalled that in the V or VI century all cubicles facing the Galleria dei Quattro Coronati were walled up [11, p. 238], including cubicle 58 with the apostle Peter's fresco. Part of the wall, with a hole to enter the cubicle, is also shown in the watercolor reported in Figure 7a (right part of Figure   7). Testini suggests that the walls were built to reinforce the tunnel and thus allow a larger number of visiting pilgrims to the cubicle of the Quattro Coronati [11, p. 238], cubicle no. 54 in Figure 14.
However, it is curious that to favor the influx of many pilgrims, someone restricted the tunnel by building a side wall. We think that the cubicles were walled up to hide any possible reference to St Peter apostle, including the watercolor, in years of destruction and profanation due to barbarian invasions.

Precision of the complex design: Fine tuning
In Section 6.2, we have shown that lines 1 e 4 intersect at the cubicle no. 58 (point 1 in Figure 12). We explore now how the coordinates of this intersection depend of the input data, namely the diameters of the Mausoleum and apse. As recalled, the Roman architects designed lengths preferably using multiples of 10 Roman feet [32, p. 118]. Let us adopt the closest multiples of 10 for the diameters, see Table 2. We notice that the largest variation is about 1 m for diameters, 0.5 m for radii, equivalent to the thickness of a wall. It is sufficient to use just these small variations to appreciate the extreme sensitivity of the intersection point coordinates. Figure 15 shows the intersections obtained with the diameters listed in Table 2. We notice that = 4°, because of constraint due to the wall of the cemetery of the Equites Singulares Augusti, but the specular angle is ′ = 3.2°. Now lines 1 and 4 and lines 2 and 3 intersect at new points (red small circles), at about 14.3 m from 1 and 2 . Therefore, differences in diameters of only 2 or 3 feet (about 1%) give differences of 14 m, about 8% of the distance between the origin 1 and the cubicle 58. No intersection falls on the cubicle 58. In conclusion, there must have been a very "fine tuning" of the lengths of the diameters to end up in 1 (cubicle 58) and in 2 . Our hypothesis is that this fine tuning was done on purpose.   Table 2. Lines 1 and 3 are no longer specular with respect to the − axis, because ′ = −3.2°, not 4° and none of the intersections of the four lines (red and green circles) falls on the cubicle 58.

Conclusion and future work
At the light of the many elements analyzed, and especially those of the last section, we conjecture that St Peter's crypt, very likely still containing his remains, could be located at the second level of the catacombs of SS Marcellino and Pietro -in the suburbs of Rome known as Tor Pignattara -very close to point 2 indicated in Figure 12. Our conjecture is very well supported by several historical and archeological elements recalled in detail, but also by our striking discovery concerning the unusual architectonic characteristics of the Basilica and Mausoleum, inexplicable in the ordered and mostly symmetrical architecture of the Roman world. Our mathematical analysis has shown that the Basilica and Mausoleum were part of a single architectonic plan, very likely designed for coding important data useful to locate Peter's burial site unambiguously.
It is very striking that Maria Valtorta, the Italian mystic consulted by the Vatican on where Peter's remains might have been buried -as we have recalled in the Introduction -, in her writings [54] indicated the catacombs of Marcellino and Pietro, and even described, with many details, the