He was born at Bruges, or, according to other sources, at Roulers.
Willaert, taught in Paris by Jean Mouton, disciple of Josquin Des Prez, first went to Rome in 1516, then to Ferrara, where he served cardinal Ippolito I d'Este, perhaps residing with him in Hungary from 1517 to 1519.
Upon Ippolito's death in 1520 he entered the service of duke Alfonso, where he remained until 1527, when he was appointed choir master (maestro di cappella) of St. Mark's at Venice. Although grounded in the principles of contrapuntal art, Willaert soon fell under the influence of the new tendency, developing in Florence and elsewhere in Italy, to make the harmonic element predominate over the melodic.
As there were two choir lofts, one of each side of the main altar of St. Mark's, both provided with an organ, Willaert divided the choral body into two sections, using them either antiphonally or simultaneously. He then composed and performed psalms and other works for two alternating choirs. This innovation met with instantaneous success and strongly influenced the development of the new method.
Willaert was no less distinguished as a teacher than as a composer. Among his disciples are: Cipriano de Rore, his successor at St. Mark's; Costanzo Porta; Francesco della Viola; Giuseppe Zarlino; and the two Gabrielis, Andrea and Giovanni. These formed the Venetian school. Willaert left a large number of compositions - 8 masses, over 50 hymns and psalms, over 150 motets, about 60 French chansons, over 70 Italian madrigalss and several instrumental pieces (ricercares).
This entry is based on the 1908 Catholic Encyclopedia article. Update as needed.