Collecting antiquities was a princely pastime that required time, space, money, access to the art market, and to the right advisers. Such collections were gathered in competition with other princes and displayed in the owners' residences as one of the many manifestations of a choreographed court culture. The aim was to present the prince and collector as a person of taste and discernment; frequently the collection was also used to make political statements that had little to do with an interest in ancient art. Cosimo I de' Medici (1519-1574) collected antiquities from the moment he became Duke of Florence in January 1537. In so doing, he continued a family tradition from the previous century and also connected with the cultural politics of the main line of the house of Medici. In some cases he even managed to recuperate antiquities once owned by Lorenzo il Magnifico. His collections, growing over nearly four decades, were also fed by gifts, chance discoveries, and acquisitions from Rome. The antiquities were stored and displayed in several rooms in Palazzo Vecchio and Palazzo Pitti that were open to visitors at the court. Scholars and artists also showed interest in these objects and started to develop an art historical framework that took into account differences in provenance, style, or material. This study is exploring the collections and the collector's aims in putting together one of the major examples of a princely collection of antiquities. Both the categories of the objects and the forms of display adopted at different times during Cosimo's reign are discussed in the historical context of a developing and expanding independent principality. Using a wealth of (mostly unpublished) archival sources, this volume attempts to reconstruct as far as possible the collection and its display in Florence. It also sets out the archaeological and artistic context of Cosimo's collection of antiquities that survives in part in the Florentine museums.