Isaak, Heinrich

(ca. 1450-1517)

   Netherlandish composer. Although born in the duchy of Brabant, he followed the pattern common in the lives of many Netherlandish composers by making his career abroad. His most important employment was in Florence during the high point of the Florentine Renaissance under Lorenzo de'Medici. He served the Medici family but was also a singer in the chapel of San Giovanni and in the cathedral choir. After Lorenzo's death in 1492, he was employed by the Emperor Maximilian I. In the emperor's service, Isaak enjoyed relative freedom of movement and lived at Vienna, Innsbruck, and Constance. He also spent time at the court of Ercole d'Este, duke of Ferrara, and he spent the last years of his life back in Florence, where he had married the daughter of a prosperous butcher.

   Isaak produced many musical compositions, both religious and secular. His Choralis Constantinus, a set of liturgical offices covering the whole ecclesiastical year, is a remarkable synthesis of the tradition of Flemish music out of which his own career developed. One of his most admired works was his musical setting of the lament for the death of Lorenzo de'Medici composed by the Florentine humanist and poet Angelo Poliziano. Isaak's secular compositions are even more highly regarded than his ecclesiastical music. They include settings for vernacular poems by Poliziano and a number of three-part and four-part German songs.