Heinrich (Hendrik) Isaac (ca.1450 – 26/03/1517) Ysaac, Ysaak, Hendrik, Henricus or Arrigo il Tedesco is a Netherlandish Renaissance composer of south Netherlandish origin province of Flanders or Brabant. Little is known about Isaac's early life but it is probable that he was born in Flanders, probably in Brabant. During the late 15th century in the Southern Netherlands, the standards of music education in this region were excellent. Isaac belonged to the third generation of South Netherlandish composer.
Isaac's career spanned well over thirty years and allowed him to travel far from his homeland of Flanders into Germany, Italy, and Austria, as well as other parts of central Europe. The first document mentioning his name dates back to 1484, placing him in Innsbruck as a singer for Duke Sigismund (1427-1496) of Austria, of the House of Habsburg. In 1485 Isaac migrated to Florence It was a start of Isaac's long stay in Florence under the employment of Santa Maria del Fiore and Santissima Annunziata as a singer. Isaac may have developed a close working-relationship with Lorenzo de Medici (1449-1492). During his presence in Florence from 1484 until the end of 1496, Isaac composed several masses, motets and secular songs. Isaac's relationship with Lorenzo de' Medici must have been fairly close. Moreover, when Lorenzo died in April 1492 Isaac composed certainly one motet in his memory the famous: Quis dabit capiti meo aquam. Lorenzo's son Piero (1472-1503) inherited everything he owned, including his musical groups. In September 1492 Piero took his musical groups to Rome to perform for the coronation of Pope Alexander VI (1431-1503). The group was dissolved. Isaac married a daughter of Piero Bello around 1494.
In November 1496 after Isaac and his wife spent some time in Pisa, they moved to Vienna and became employed by Emperor Maximilian I ( 1459-1519). In April 1497, Isaac was appointed court composer for Maximilian I. Isaac remained under Maximilian's employment from 1496 until his death. Isaac traveled extensively around Europe north of Italy with the court to Torgau, Augsburg, Nürnberg, Wels, and back to Innsbruck between 1497 and 1501. In 1502, Isaac returned to Italy, going again to Florence. Isaac traveled to Ferrara to the Este court. Isaac competed with Josquin des Prez (c.1440-1521) for an appointment. Some later between 1505 and 1512 Isaac stayed in Augsburg and Konstanz. Isaac compiled here his largest set of works: Choralis Constantinus. In Konstanz Isaac met his pupil Ludwig Senfl (c.1486-1543).This monumental collection of mass propers was commissioned by the Constance cathedral on 14 April 1508 and completed by Isaac and his student Ludwig Senfl by the winter of 1509. In 1512 Isaac went back to Florence and spent there the last part of his life. He was given an honorary position as maestro of the chapel at Santa Maria del Fiore in 1514, which served as a pension. Isaac passed away on 26 March 1517. Isaac was one of the most prolific composers of the time, producing an extraordinarily diverse output, including almost all the forms and styles current at the time. Music composed by Isaac included masses, motets, songs in French, German, and Italian, as well as instrumental music. 36 of his settings of the ordinary of the mass survived; Numerous individual movements of masses survived as well. But Isaac’s setting of music for the Proper of the Mass – the portion of the liturgy which changed on every day, unlike the ordinary, which remained constant – which gave him his greatest fame. The huge cycle of motets which Isaac wrote for the mass proper, the Choralis Constantinus, (containing about 450 plainchant based polyphonic settings) and which Isaac left incomplete at his death. This cycle supplied music for 100 separate days of the year. It was published in three volumes between 1550-1555. Those motets remain some of the finest examples of plainchant-based Renaissance polyphony in existence.
Isaac’s influence in Germany and Austria was great. Isaac was the first great South Netherlandish composer who became famous and whose music was widely distributed there. The polyphonic style of the great distinguished Netherlandish composers was accepted through him in Germany and Austria and this music could be further developed in that region even by other famous Netherlandish composers and musicians to follow.