An extensive analytical study has been performed on a large number of gold coins (Norman-Swabian Augustale and Tarì, Grosso of Lucca, Florin of Florence) minted in Italy from the end of XII century to XIV century. The X-ray fluorescence (XRF) technique was used for verifying the composition of the coins. XRF is a nondestructive technique particularly suited for in situ quantitative analysis of gold and minor elements in the precious alloy. The Florins turned out to have a gold content very close to 24 carats (pure gold) although in a couple of cases we observed relatively high concentrations of iron (around 2%) or lead (around 1%). The Grosso of Lucca has a similar composition, with a measured gold content around 97% due to a higher silver percentage (about 2%), with respect to the average Florin. The Augustali analyzed showed, on average, a gold content around 89%. The average gold content of the Tarì analysed is around 72%, with a relatively large variability. The analysis revealed the use of native gold for the coinage of the Florins, excluding the possibility of recycling gold coming from other sources. On the other hand, the variability observed in the compositions of the Tarì and Augustali could suggest the reuse of Islamic and North African gold. The study could shed some light on the sudden diffusion of gold coins in Italy around the first half of XIII century, allowing hypotheses on the provenience of the gold used for a coinage that dominated the economic trades from then on. 1. Introduction The analytical determination of ancient coins’ composition is important for gathering information about the historical situation and the commercial exchanges at the place and time of their coinage [1–3]. However, it is also a particularly challenging task that has to take into account the historical, numismatic, and economic value of the object under study. The analytical methods routinely used for the laboratory analysis of metallic samples in most of the cases cannot be used because of the intrinsic destructivity of most of those techniques [4, 5]. In fact, even when the importance of the analysis would justify the sacrifice of some coin, the results gathered on a very limited number of samples may suffer from the lack of reproducibility associated with the poor statistics. In recent years, the introduction of cheap, portable X-ray fluorescence (XRF) instrumentation seems to have changed this scenario, providing a viable solution for the nondestructive analysis of scarce or very precious coins but also for the study of a large quantity of samples,
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