Whatever the castrati's talent for fioritura, they carried the dramatic burden of the opera, and the martial roles were sung by them. Contem- porary accounts of their voices almost invariably stressed the size of those voices. An examination of Adriano in Siria, written for Caffarelli by Luigi Pergolesi in 1734, confirms not only the singer's technique and breath, but also his power. In the aria “Sul mio cor,” he sang sustained notes in every register, whether after octave leaps or descents and whether or not he had been singing extended trills—all without any discernible opportunity to breathe for bars on end. Indeed, once, after a long passage that provided no place to take a breath, he concluded by trilling on sustained notes while the orchestra played forte. Other arias in that opera also demonstrate equivalently the skills of its castrato hero and the dramatic nature of his voice, not to mention a range that in one aria, “Torbido in volto,” carries him from high C to low B-flat and back again several times.