Diego Ortiz is important to history not only as a leading Spanish composer of the Renaissance era, but also as the author of Trattado di glosas, the first printed instruction book about ornamentation for bowed string orchestras. This was an international success, and was published in Italian. The book contains entirely written-out ornamentations designed to fit specific time periods. The player is directed to determine which was most appropriate, and to write it into his part at the right spot. Furthermore, the work contains studies for bass instruments, treble viol, and keyboard, as well as some madrigals. Like most authentic books on ornamentation and instruction of the period, it is a valuable source of information on performing style of the time. Not much is known about Ortiz's life. The two versions of his book were published simultaneously (in December 1553) while he was in Naples in the service of Pedro de Urries, a Spaniard who was Duke of Riesi, Sicily. The Italian edition is full of Spanish turns of phrases, which suggests that it was prepared by Ortiz himself, and that the writer had been resident in the Spanish-ruled Italy for some time. By February 1558 he was named maestro de cappella for Fernando Alvarez de Toledo, Duke of Alba and the Spanish Viceroy of Naples, and kept that position (or perhaps was rehired for it after a hiatus) by the next Viceroy, Pedro Afán de Rivera, Duke of Alcalá, to whom he dedicated his Musices liber primer, which includes some Magnificat settings, all based on plainchants.