It has to be presumed that the second copy of Così fan tutte which contained Mozart's revised version V2 is lost, but we have already encountered many signs of its existence. The likely contents of this all-important source can best be reconstructed from the score Ca in Harvard, which stems from a branch of Transmission Line B. For Act I at least, the very closely related score S provides additional confirmation, while Treitschke's decision to use it as the basis for his 1804 translation Mädchentreue confirms the essential integrity of this revision as a ‘version’ of the opera. Unusually for an early copy of a Mozart opera, there are indications that Ca was at one time owned by an English speaker. Ferrando's Act I aria was restored (or perhaps repositioned) with the comment ‘Un aura amorosa comes next’. The score is, however, unconnected to the 1811 London première which was based on a very different version. The copyists hands do not show features of the Viennese system, yet the Harvard manuscript is of considerable significance, since it incorporates all the new cuts and revisions that define Mozart's revised Vienna version. These are listed in Table 28.

The score Ca also provides a fascinating glimpse into how V2 must have looked before the ‘agreed’ recitative cuts were sealed. It is quite clear that at this early stage these cuts were identified in some way, but in a manner that was wide open to misinterpretation. The original copyist who started the branch of transmission from which Ca derives, notably failed to understand some of these indications. The mistakes are listed in Table 29.

A fascinating page in Ca is the start of the recitative ‘Ah non partite’. The first intervention from one of the sisters (‘E che pretendereste’) is clearly attributed to Fiordiligi, and thus Dorabella does not sing anything. (It will be recalled that Mozart first gave this phrase to Fiordiligi in the autograph and then changed the part label to Dorabella.) If Fiordiligi had once been the only sister present, that would certainly explain the use of the singular ‘ragazza’ with which Don Alfonso refers to her.