King Friedrich Wilhelm II of Prussia (1744-1797) had a strong interest in Boccherini's music already from his time as Crown Prince. His collection contained almost the complete published oeuvre of the composer, acquired before Boccherini's official employment with him begun, in January 1786. In this year, Boccherini was appointed Compositore di Camera, a position he retained until the end of the king's life in November 1797, and during which time he kept sending his works to him. By the end of the king's life, his collection contained –in addition to the printed music– a substantial number of manuscripts of unpublished works by the composer, becoming one of the largest collections of Boccherini's instrumental works. This article discusses Boccherini's dealings with the Prussian Court, as well as the court's copying and performing practices of his works, drawn from the surviving catalogues of the king's music collection.