By these masters, at the instance of the Magnificent Lorenzo, this art of engraving in intaglio was taught to a young Florentine called Giovanni delle Corniole,[12] who received that surname because he engraved them excellently well, of which we have testimony in the great numbers of them by his hand that are to be seen, both great and small, but particularly in a large one, which was a very choice intaglio, wherein he made the portrait of Fra Girolamo Savonarola, who was adored in Florence in his day on account of his preaching. A rival of Giovanni was Domenico de' Cammei,[13] a Milanese, who, living at the same time as Duke Lodovico, Il Moro, made a portrait of him in intaglio on a balas-ruby greater than a giulio, which was an exquisite thing and one of the best works in intaglio that had been seen executed by a modern master. This art afterwards rose to even greater excellence in the pontificate of Pope Leo X, through the talents and labours of Pier Maria da Pescia, who was a most faithful imitator of the works of the ancients; and he had a rival in Michelino, who was no less able than Pier Maria in works both great and small, and was held to be a graceful master. These men opened the way in this art, which is so difficult, for engraving in intaglio is truly working in the dark, since the craftsman can use nothing but impressions of wax, as spectacles, as it were, wherewith to see from time to time what he is doing. And finally they brought it to such a condition that Giovanni da Castel Bolognese, Valerio Vicentino, Matteo dal Nassaro, and others, were able to execute the many beautiful works of which we are about to make mention.