Throughout the foregoing discussion of hypotheses relating to the composition of Così fan tutte, the autograph has remained our central source, yet there have also been repeated references to the Vienna Court Theatre score (V1) because of the light that it can shed on the later stages of the compositional process. It is now time to consider in more detail the nature of this source (and of subsequent copies). The justification for so doing is that our modern understanding of what a compositional history should entail, extends well beyond what exists in the composer's autograph, and, indeed, beyond what can be shown to have been performed at the première itself; it must also embrace subsequent changes made to the opera by, or directly on behalf of the composer, during his lifetime. In this endeavour, the Court Theatre copies come into their own as documents of equal significance to the autograph.

One of Tyson's landmark contributions to the study of Mozart's operas was the discovery of the importance of the early manuscript copies. Once an opera had been accepted for performance in Vienna, at least two copies were produced almost simultaneously. I have labelled them V1 (the reference copy) and V2 (the conductor's copy). The firm regularly employed for this task during Mozart's later Vienna years was headed by the Moravian Wenzel Sukowaty, an analysis of the activities of whose ‘copy shop’ forms a major part of Edge's thesis.After the end of the first production run, the reference copy was retained, and if further scores were required for productions elsewhere, they were almost always purchased from this source. The autograph remained in the composer’s possession, but the fate of the conductor's copy was altogether less certain. Tyson demonstrated convincingly that small changes made during the rehearsal period were entered in a theatre copy rather than the autograph. In the case of Così fan tutte the composer himself seems to have marked up the conductor's copy V2, and then the changes were quickly transferred to the reference copy V1 by an assistant.