This work enters in an interdisciplinary research project involving the archaeometrical analysis of ancient silver coins minted in the Greek colony of Taras (the modern south Italian town of Taranto) between the V century BC and the III century BC. In this work, by comparing the results obtained from X-ray microanalysis data acquired from the least corroded surface areas and the cross-section of coins from SEM-EDX and from XRF analysis, we have demonstrated that analysed coins exhibited a corrosion layer no more than 25？μm and that surface silver enrichment was less than 1？wt%. Thus, the data obtained by using X-ray microanalysis from surface may not significantly differ from the original bulk composition. Our results demonstrate that the silver content in the coins decreases considerably ranging from about 97% for the older down to 80% for the ones of 3rd Evans period (300–270？BC), corresponding to the significant social change in the period. 1. Introduction The cooperation between analytical physicists and numismatists is in expansion because they are confronted with problems that traditional methods of numismatics cannot solve. Elemental analysis of ancient coins presents increasing interest due to their direct relation with economy and metallurgy of the minting time. The minting time is usually determined with very good accuracy by the numismatists from the examination of the features of the coin. There are three separate areas of interest where cooperation can take place between the scientist and numismatist: (1) results of analysis for major components may provide information on the minting technology of the period [1, 2] and may also help in studies of economical development [3]; (2) the determination of the minor and trace elements can give suggestions regarding the provenance of the metal used [4–10] or contamination introduced during manufacture; (3) microscopic examination may yield important information regarding the type of metallurgical processes used during the manufacture of coins [1]. Coinage has always been a prime target for debasement or production of copies of ancient issues because of the immediate financial reward that results [11]. It has been known for a long time that the chemical composition on the surface of old coins sometimes differs from that in the bulk [12, 13]. The advent of accurate and nondestructive physical techniques, such as X-ray fluorescence analysis (XRF), electron probe microanalysis (EPMA), and particle induced X-ray emission (PIXE), was synonymous with great changes in metallic analysis applied to
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