Because of its bearing on his freelance career, the question of private patronage in Vienna during the 1780s is of great interest to Mozart scholarship. Serious investigation into this question, however, has been hampered by a lack of sources. The chief source to date has been the Mozart correspondence, especially Wolfgang's letter of 20 March 1784 to his father, in which he lists the subscribers to his forthcoming concert series. Another valuable source exists in the Zinzendorf diaries, which, although often dipped into, have not been systematically examined for their potential in this regard. My recent transcription of all the passages in the diaries that deal with theatre and music in Vienna from Easter 1783 to Easter 1792 includes the private entertainments of the nobility in whose circles Zinzendorf moved. These are summarized in Appendix 1, which forms the basis of the present discussion.