For the forthcoming autumn/winter season, La Scala had engaged Giulia Grisi (the sister of Giuditta Grisi) and the well-known tenor Domenico Donzelli, who had made a name for himself with Rossini roles, especially that of Otello. They would fill the roles of Adalgisa and Pollione. Donzelli provided Bellini with precise details of his vocal capabilities which were confirmed by a report which the Neapolitan composer Saverio Mercadante also provided. By the end of August it appears that Romani had completed a considerable amount of the libretto, enough at least to allow Bellini to begin work, which he certainly did in the first weeks of September as the verses were supplied. He reported in a letter to Pasta on 1 September: