While symphonies were likely to receive a wider distribution, it was concertos that constituted the “meat and potatoes” of a court composer's productivity. Performers were continually in need of pieces to display their special talents. Regular performances of concertos in court concerts ensured that the skills of individual virtuosos would be obvious to their employers. Performers occasionally tried their hand at composing their own concertos, but more often than not this led to less than satisfactory results. Printed editions were available, but costly. Wallerstein musicians sometimes sought appropriate pieces from outside the court, but, of course, their composer colleagues in the prince's Hofkapelle offered the most accessible resource for new solo works. Unfortunately for the historian, most of these agreements were made directly between performer and composer, and thus not recorded in court records. The Wallerstein Hofkassa includes numerous receipts for the copying of symphonies and wind partitas, but few for concertos or other types of solo literature. Concertos commissioned from a house composer by one of his colleagues frequently ended up among the personal property of the performer. Although at his death the composer's descendents might sell, or perhaps even donate, this music to the court music library, this was not always the case. Our knowledge of these private music collections derives chiefly from the accounts of a musician's estate, their Nachlass. The Wallerstein archives include such inventories for three court musicians active at the same time as Rosetti.