Tin Isotopes and the sources of Bronze Age tin in the Old World At CEZA, a project funded by the European Research Council (Advanced Grant 2012, project no. 323861) has developed a new method to solve the old mystery of where the alloy of copper and tin that gave its name to an entire era came from. The geochemical parameters that can be determined in bronze only indicate the origin of copper but not of tin. The aim was the possible differentiation of tin deposits by means of natural variations of the isotope ratios of tin, which were not known before. This geochemical parameter should make it possible to assign tin to specific deposits. Archaeological finds from the 3rd and 2nd millennium B.C. were investigated, when tin bronze first appeared and then became the standard material for tools, weapons and jewellery. The origin of the earliest tin is the focus of the research project Report A new method for the precise measurement of tin isotope ratios in both archaeological bronze and tin artefacts and tin ores was developed and a reference material was produced to facilitate international comparability of analytical results. In addition, extensive experiments were carried out to test whether changes in tin isotope ratios occur during the various production and processing steps of tin and bronze. This is indeed the case and a correction factor has been calculated in order to be able to compare the analysis results of ores and metal objects. The results showed that there are sometimes considerable variations in the tin isotope ratios in tin deposits, but that the variations within the deposit provinces are relatively large, so that there is overlap between different provinces and it is not possible to make a clear distinction. This is particularly true for the large regions of the Erzgebirge and Cornwall. However, individual deposits within the provinces can be identified and, together with other parameters such as lead isotope ratios and trace element patterns, the use of tin from Cornwall in the eastern Mediterranean in the 2nd millennium BC has been demonstrated. On the other hand, it could be shown that tin bronze technology did not first spread from the Aegean to south-eastern Europe, but that tin bronze was used in Central Europe on a small scale earlier, whereby the tin probably came from Cornwall (Nebra Sky Disk) and the Ore Mountains (bronze finds of the Aunjetitz Culture). In Mesopotamia and Anatolia, where tin bronze appeared as early as the 3rd millennium B.C., the tin isotope ratios in artefacts show a wide variation, which indicates that tin was obtained from different sources.