While Josquin Desprez is unquestionably the major figure of the middle Renaissance period, there are many other outstanding names that deserve attention. Above all, the music of Heinrich Isaac -- another exceptionally versatile composer of the Franco-Flemish school -- stands out from this particularly rich period of musical composition. Born some ten years after Josquin, Isaac (ca. 1450-1517) is likewise a composer whose early life remains obscure. After 1480 he is known to have been in Florence in the service of Lorenzo the Magnificent, a member of the powerful ruling Medici family; Lorenzo was responsible for Isaac's appointment as organist of the cathedral. Following the fall of the Medicis in 1497, he was appointed court composer to the Emperor Maximilian I in Vienna and Innsbruck, but his heart remained in Florence, to where he made frequent return journeys before finally settling there three years before his death in 1517. Isaac was typical of his time in his travels to and from Italy, and his large body of compositions reflects to an unusual degree the cosmopolitan nature of the international Franco-Flemish school of the age; his secular works show him to have been equally at ease with German, Italian or French song. The Italian songs are strongly influenced by the frottola, a kind of simple, light song that largely avoided polyphony in favor of catchy dance rhythms. Many of them were doubtless composed for the frequent Florentine carnivals; their relatively small number is likely due to the religious fanatic Savonarola's wholesale destruction of "profane" repertoire in the aftermath of the downfall of the Medicis. One such Isaac song, "Ne più bella di queste," celebrates the city that held such an inescapable fascination for him; it ends with the words, "all the earth sings and laughs in Florence and says Florence is paradise." Among Isaac's German songs, "Innsbruck, ich muss dich lassen" is perhaps the best known; it too is simple in style, with predominantly homophonic writing and an elegant melancholy that looks forward to the era of the madrigal. Depending on which authority one consults, Isaac is said to have composed anything between ten and thirty masses, a discrepancy that significantly illustrates just how little attention has so far been devoted to this aspect of his work. In contrast to those of most of his contemporaries, many of Isaac's sacred works employ a rich six-part palette, a format he adopted in the Missa de Apostolis. This is one of the masses composed during Isaac's service at Maximilian's court, and, in common with Austrian practice at the time, it omits a polyphonic setting of the Credo, and alternates polyphony with plainsong in the remaining sections of the Ordinary. Despite such telescoping it is an expansive work, amply demonstrating the composer's love of contrasting sonorities, long melodic lines, and -- when compared with Josquin -- less tightly organized polyphony. During a sojourn in Konstanz around 1507, Isaac began the composition of a huge cycle of Mass Propers; these appear in the monumental three-volume Choralis Constantinus, the first known integral set of music for the propers for the whole ecclesiastical year. On Isaac's death his student Ludwig Senfl set about completing it; it was not published until 1555.