 These pairs became Opus 1 and Opus 2 in Leopold's private catalogue of his son's work.The first pair was dedicated to the king's daughter, Madame Victoire de France, the second to the Countess of Tessé.Mozart biographer Stanley Sadie comments that some aspects of these pieces are rather childish and naïve, but that nevertheless their technique is "astonishingly sure, their line of thinking is clear and smooth, and their formal balance is beyond reproach".