Search Results (18)

History attempts to make sense of disparate information by trying to create discourse that lays a series of events with crisp cause–effect relationships in a sequence. Epochal shifts, such as the change from Antiquity to the Middle Ages, are especially complex since they involve a large number of economic, political and even religious factors which occur over long periods and that might overlap and interact through reciprocal feedback mechanisms, making this cause–effects sequence difficult to establish. In this research we adopt a data-driven and well-established methodology to identify, with quantifiable statistical precision, the moment when this shift happened, and from there arrive at its possible causes. We will use historical coin hoard data to find out whether such a shift is detected in a peripheral part of the Roman Empire, the Iberian Peninsula. To do so, we will apply different changepoint analysis methods to a time series of trade links created from that data, and conduct a retrospective analysis based on that result, analyzing the structure of the trade networks before and after the link. Thus, we progress from identifying when the shift happened to identifying where it took place, which in turn allows us to get to investigate why it happened, namely, historical events that could have caused it. This methodology can be used to analyze epochal changes in several steps using time-stamped network data, possibly finding disregarded causes or cause–effect links that could have been overlooked by qualitative methods; in this case, we have applied it to a dataset of coin hoards either found in the Iberian Peninsula or including coins minted there, finding a changepoint in the early 5th century, which, through network analysis, has been linked to a loss of trade with the area of Britannia. Full article

This study investigates 49 gold solidi issued between the 4th and 5th century AD to determine their chemical composition. The coins were first catalogued by recording mass, diameter, and thickness. All specimens underwent non-destructive µ-EDXRF analysis to identify main elements, followed by semi-quantitative fineness evaluation. To validate these results, six coins were randomly micro-sampled: material was dissolved in aqua regia and analysed by ICP-AES for gold quantification and ICP-MS for high precision trace element determination. The non-destructive analyses showed consistently high gold percentages, confirming authenticity and the extensive use of this noble metal during the studied period. Two distinct groups were identified based on the XRF Pt/Pd ratio, suggesting the use of gold from different sources. Comparison of μ-EDXRF and ICP-AES gold contents shows no statistically significant differences; however, this apparent agreement should be interpreted cautiously, as it mainly reflects the limited resolving power of ICP-AES at very high gold concentrations rather than definitive evidence for the absence of surface-related effects. Trace elements analysis detected low concentrations of Cu, Sn, and Pb suggesting the use of alluvial gold for minting. The presence and correlation of terrigenous elements (Al, Ca, Ti, Cr, Mn, Fe, Ni, Zn, Sr) indicate soil as the burial site. Full article

A novel forming process was developed to create rotating elements in collector coins by shaping thin-walled tubes into toroidal shells in a single stage. This process introduces new aesthetic effects and functionalities to the coin market. By controlling the end-forming of a tube, a gap is created between the toroidal shell and the coin blank, allowing free rotation. The technique, a modification of conventional tube end inversion, results in distinct deformation mechanics. Through finite element modeling and experimentation, key process variables were identified, ensuring sound hollow toroidal shells with efficient rotation. Full article

A series of 11 Byzantine gold coins were investigated, including two examples of an extremely rare type called histamenon “stellatus”, from around the reign of the Byzantine emperor Constantine IX Monomachos (AD 1042–1055). The methods applied were X-ray fluorescence spectroscopy (XRF), specific density measurement (SD), and scanning electron microscopy (SEM). The debasement (decreasing gold content) of the Byzantine nomisma gold coinage during the 11th century was demonstrated. A method combining XRF and SD measurement combined with a graphical presentation/analysis called a ternary plot was also demonstrated. The measured gold content of the 11 coins was corrected for the possible “outwashing” effect and a potential cleaning of ancient gold. A model for the estimation of the gold content of Byzantine histamenon nomisma gold coins from the period AD 1020–1118, based on the specific density (SD), was derived. It was demonstrated that two analyzed histamenon “stellati” coins likely were minted around AD 1054–1055, possibly during the same period as the occurrence of the supernova SN1054, known as the Crab-nebula. It is further discussed if the gold content and size of the stars shown on those coins can be correlated to the visibility of the supernova from June AD 1054 to January AD 1055. Full article

Non-destructive, specular laser reflectometry, an industrially used and easily accessible method, is adapted in numismatic research to the inspection of coins of the Gallic Roman Empire with the objective of the allocation of mints and/or the identification of different minting techniques. For this purpose, the laser-reflectometric fingerprints of three series of coins each consisting of five antoniniani (or radiates) of the Gallic Roman Empire originating from two mints—Trier and Cologne—are systematically determined, analyzed and correlated with the corresponding XRF element analysis. The results show that the use of an inexpensive red-emitting laser system (wavelength 632.8 nm) with a beam diameter $d<0.5$ mm and a sample mount that can be adapted to the individual shape and thickness of the coins leads to signal intensities that can be systematically recorded over a large angular range with a very good signal-to-noise ratio (SNR $>10$). While the signals cannot be used to assign individual coins to mints, we discuss the possibility of a statistical analysis. Although each coin set consists of only five samples and thus requires further study, the results here suggest that the sets can be distinguished from each other, that there is a correlation to the silver concentration and that it is possible to estimate the refractive index n. Full article

The colonisation of the Americas and the discovery of its rich ores had a great impact on the world economies, making them quickly become the main suppliers of precious metals in Europe. The compositional studies of several coins (ducatons, eight reales cob8, four reales cob4, eight reales pillar dollar, four reales half pillar dollars, rijderschellings and silver rijders) recovered from the 18th-century Dutch East India Company Rooswijk wreck by micro X-ray fluorescence (µXRF) spectroscopy revealed further knowledge about the silver trade and the silver sources used to produce coins in mints in the Low Countries over a wide timeframe (1618–1739). The results provided trace elemental ‘fingerprints’ of coins minted with silver from known mines, and matching against them revealed the silver sources used in coins, whose mint location could not be identified due to their poor state of preservation. This study proved that, despite the decrease in silver production in European mines in the 17th century and the huge influx of American silver into Europe, in the 18th century, the mints in the Dutch Republic and, to a lesser extent, in the Spanish Netherlands still highly relied on the recycling of older coins and on the import of silver from central European mines. Full article

Over time, many minted coins were withdrawn from circulation, being replaced with new ones. The returned, obsolete metal coins were melted in order to ensure sustainable reuse of the alloy for other purposes. Between the withdrawal and melting, some of the metal coins were canceled by the destruction of their original shape and dimensions using adequate tools. The first part of this paper is focused on presenting some insights into the canceling method used on old Romanian nickel coins; also, some examples are presented. The introduction also includes a literature review in the field of coin manufacturing, covering subjects such as metal behavior under striking load and aspects of 3D modeling and FEM analysis as well as explaining some striking errors. The main purpose of this paper is to study the particularities of canceling methods applied to coins, which is conducted on relatively valuable collection metal pieces. In the second part of the paper, an adequate 3D model is computed for the canceling dies and the coin. Then, the assembled models are introduced, corresponding to each canceling case, consisting of the obverse and reverse canceling dies with coins inside them. For each model, the finite element analysis is realized and is achieved for different initial conditions. The final part of the paper presents the analysis results as well as the discussion and conclusions. Full article

We report here the results of a multi-analytical approach to characterize twelve Roman coins dating from the third century B.C. to fifth century A.D. that were found in the surroundings of Rome and for which the year of minting is determined by numismatic analysis. The coins were studied using SEM-EDS, EMPA, XRD, and FTIR techniques, enabling semi-quantitative and quantitative determinations of the chemical and mineralogical composition of the alloys and corrosion products. SEM-EDS analyses highlighted the occurrence of corrosion products on the surfaces and wide chemical variations due to selective enrichment or depletions of the alloying metals. The EMP analyses showed that three of the twelve coins are made of copper (1), one is a copper–tin alloy (2), five are copper–tin–lead alloys with elements in different proportions (3), two are copper–lead alloys (4), and another one is a subaerata coin (5). In addition, the physical parameters of the coins, i.e., density, weight, and diameters, were measured to have an overall characterization. Full article

A sample of 18 double-relief coins from different poleis of Magna Graecia and ancient Italy has been analysed using a handheld XRF spectrometer directly inside the Museo Provinciale Campano (Capua, Italy). The data analysis shows that (i) the main elements are Ag and Cu, indicating that the coins are of high fineness (average Ag 95.7%), (ii) trace elements can help to characterise the coins, (iii) a superficial chemically altered layer (corrosion) is absent, (iv) the values of ratio Ag Kα/Lα evidence the presence of an enrichment layer on the surface of silver or subaerata in some coins. Multivariate statistical analysis and graph analysis allowed the coins to be assigned to different groups with the highest possible accuracy on the basis of the chemical data obtained and models to be constructed to classify the coins according to their historical periods. Full article

The paper presents the first archaeometric results on a selection of ancient Roman coins (antoniniani) from a treasure found in the Roman necropolis area of ancient Cumae (Southern Italy) during archaeological campaigns by the Centre Jean Bérard. A multi-analytical approach consisting of non-destructive techniques (stereomicroscopy, FESEM-EDS, pXRF, Raman, μ-CT) was implemented on the better-preserved coins of the treasure in order to investigate the chemical composition of the alloy. Chemical analysis showed that the Roman mint prepared the metal with an argentiferous lead–bronze alloy. A group of coins presents a low content of the precious metal, which is in agreement with the financial crisis of the Roman Empire of the third century. Another group of two coins shows a higher silver content, which is in agreement with their issue or with the Mediolanum mint standards. In addition, the external layers of corroded coins were analysed to explore the state of conservation of the patina and to identify the corrosion products. Some typical corrosion patinas due to post-depositional conditions were identified. The mineralogical characterisation of the corrosion products enables us to implement adequate conservation strategies, and the presence of more aggressive patinas suggests immediate interventions. Full article

The present research is focused on the 3-Polker coins issued during 1619–1627 by Sigismund III Vasa, King of Poland. A major financial crisis took place at that time due to the 30-year War, which started in 1619. There are two theories among historians concerning the silver depreciation of these coins. The most common theory (generally accepted without proof) is that the later years of issue are depreciated below 60% Ag. The second theory is based on the medieval sources that indicate inflation during the years from 1621–1625, but the medieval source only refers to the inflation of the type of coins and does not mention the issuer. Therefore, in this study, we use modern investigation techniques and materials science methods to help historians elucidate the aforementioned aspects regarding the medieval period. The XRD investigation results are in good agreement with the SEM-EDX elemental analysis. The coins from 1619 and 1620 have high silver content, namely, 86.97% and 92.49%, which corresponds to good silver. The amount of Ag found in the coins from 1621–1625 issituated in the range of 63.2–74.6%. The silver titleis suddenly restored in 1626 at about 84.3% and is kept in a good range until the end of this decree under Sigismund III in 1627. In conclusion, the second theory was partly validated by our experimental results, certifying the currency depreciation during 1621–1625, but the silver title was not lower than 54.2%. Notably, even this depreciated silver title assures a good quality of the 3-Polker coins compared to similar coins issued in other countries that were copper–silver-plated. Therefore, the 3-Polker coins were preferably hoarded at that time.Small alterations in the mint mark’s design were observed in all the depreciated coins compared to the good ones. This might be a sign for an expert to identify the depreciated coins, a fact which requires supplementary investigations. The silver title’s restoration in 1626 also came with a complete change of the mintmark. Full article

Very high fluence implantation of ${}^{14}$N${}^{+}$ ions was used to promote the formation of a nitride layer on the surface of steel coinage dies used by the Portuguese Mint. Die steel samples were studied before and after implantation at 90 keV plus 30 keV for two nominal fluences, 5.0 × 10${}^{17}$ at/cm${}^2$ and 1.0 × 10${}^{18}$ at/cm${}^2$, and for two implantation temperatures, room and liquid nitrogen temperature. Surface characterization was carried out by ultramicrohardness indentation, Atomic Force Microscopy (AFM), and Rutherford Backscattering Spectrometry (RBS). A significant increase (factor two) in depth reached by the implanted nitrogen was observed for LN2 implantations, which, to our knowledge, was never reported before. Results point out the benefit of nitrogen implantation at room temperature with a nominal fluence of 5.0 × 10${}^{17}$ at/cm${}^2$, which raised the hardness of the dies by ∼40% (from 6.2 ± 0.5 to 8.7 ± 0.7 GPa). Nitrogen implanted dies were used to mint circulating two cents euro coins and their performance was assessed, showing that when compared to Vautrol coated dies (standard coating used by the Portuguese Mint), the crack density was lower and similar wear resistance was observed. Full article

King Stefan Uroš II Milutin Nemanjić (1282—Donje Nerodimlje, October 29, 1321) was a Serbian medieval king, the seventh ruler of the Serbian Nemanide dynasty, the son of King Stefan Uroš I (r. 1243–1276) and Queen Helen Nemanjić (see), the brother of the King Stefan Dragutin (r. 1276–1282) and the father of King Stefan Dečanski (r. 1322–1331). Together with his great grandfather Stefan Nemanja, the founder of the Nemanide dynasty, and his grandson, Emperor Stefan Uroš IV Dušan, King Milutin is considered the most powerful ruler of the Nemanide dynasty. The long and successful military breach of King Milutin, down the Vardar River Valley and deep into the Byzantine territories, represents the beginning of Serbian expansion into southeastern Europe, making it the dominant political power in the Balkan region in the 14th century. During that period, Serbian economic power grew rapidly, mostly because of the development of trading and mining. King Milutin founded Novo Brdo, an internationally important silver mining site. He started minting his own money, producing imitations of Venetian coins (grosso), which gradually diminished in value. This led to the ban of these coins by the Republic of Venice and provided King Milutin a place in Dante’s Divina Commedia. King Milutin had a specific philoktesia fervor: He built or renovated over three dozen Serbian Orthodox churches and monasteries not only in Serbia but also in Thessaloniki, Mt. Athos, Constantinople and The Holy Land. Over fifteen of his portraits can be found in the monumental painting ensembles of Serbian medieval monasteries as well as on two icons. Full article

The chemical and elementary composition, internal arrangement, and spatial distribution of the components of ancient Greek copper coins were studied using XRF analysis, neutron diffraction and neutron tomography methods. The studied coins are interesting from a historical and cultural point of view, as they are “Charon’s obol’s”. These coins were discovered at the location of an ancient Greek settlement during archaeological excavations on the “Volna-1” necropolis in Krasnodar Region, Russian Federation. It was determined that the coins are mainly made of a bronze alloy, a tin content that falls in the range of 1.1(2)–7.9(3) wt.%. All coins are highly degraded; corrosion and patina areas occupy volumes from ~27 % to ~62 % of the original coin volumes. The neutron tomography method not only provided 3D data of the spatial distribution of the bronze alloy and the patina with corrosion contamination inside coin volumes, but also restored the minting pattern of several studied coins. Taking into account the obtained results, the origin and use of these coins in the light of historical and economic processes of the Bosporan Kingdom are discussed. Full article

The objective of this paper is to present a new hybrid additive manufacturing route for fabricating collector coins with complex, intricate contoured holes. The new manufacturing route combines metal deposition by additive manufacturing with metal cutting and forming, and its application is illustrated with an example consisting of a prototype coin made from stainless steel AISI 316L. Experimentation and finite element analysis of the coin minting operation with the in-house computer program i-form show that the blanks produced by additive manufacturing and metal cutting can withstand the high compressive pressures that are attained during the embossing and impressing of lettering and other reliefs on the coin surfaces. The presentation allows concluding that hybrid additive manufacturing opens the way to the production of innovative collector coins with geometric features that are radically different from those that are currently available in the market. Full article