Aaron, abbot of St. Martin, at Cologne, was born in Scotland. He wrote a work on the utility and manner of singing church music; and introduced the Gregorian nightchant from Italy into Germany. He died in 1052.

AARON, (Pietro) a Florentine of the order of Jerusalem, and canon of Rimini, was a voluminous writer on music. The most considerable of his writings is, “Il Toscanello della Musica,” 1523, 1529,1539, a rare and important work. He gave in it a decalogue, or ten precepts for counterpoint, in honour, it is said, of the ten commandments of God; and six precepts of less importance, in honour of the six commandments of the church. His works became particularly useful, from being for the most part written in Italian; whereas those of almost all the preceding musical writers were in the Latin language. Pietro Aaron gives a list of such extraordinary performers as were able to sing from notes, “Cantare a libra,” by which we may suppose that the art was then in its infancy.

ABACO, (Evaristo Felice dall') a violinist and composer, born at Verona. In the year 1726, he was musician to the court of Maximilian Emanuel.

ABACO, (Baron) also born at Verona, was an amateur performer on the violoncello and composer for that instrument. One of his pieces is dated 1748.

ABBATINI (Antonio Maria) was born at Tiferno in the year 1605. He was chapel—master of the churches of St. John of Lateran, and of Santa Maria Maggiore at Rome.