Composer Jacobus Vaet is first mentioned on the rolls of a church in Kotrijk in 1543; he is identified as being 13 years old and accepted as a boy chorister. Three years later, his voice broke, but he was able to transfer to the University of Leuven with a scholarship. By 1553, Vaet is in the service of Archduke Maximilian of Austria as kapellmeister and based out of Vienna. In 1564, the Archduke succeeded his father into the role of Holy Roman Emperor as Maximilian II, placing Vaet in a very powerful cultural position. Nevertheless, he would not enjoy it long, as Vaet died in early 1567 at about the age of 37. His death was noted widely among court poets and composers throughout Europe, and even by the Emperor himself in his private diary, as Vaet had not only led the music in Emperor Maximilian's court, but also was a valued and trusted friend. Vaet was also among the last generation of composers belonging to the so-called "Franco-Flemish School" of polyphonic music that began with Dufay. Vaet was a specialist in the realm of the parody mass. He is credited in some sources with inventing the Missa quodlibetica, an assembled mass setting that combined a variety of pre-existing melodies into a single texture. His sources for melodies included his own melodies in addition to many of his most famous contemporaries. Vaet was close friends with composer Orlandus Lassus, and the two composers seem to have influenced each other; at one time Lassus' Missa "Si me tenez" was thought the work of Vaet. Vaet also was a great admirer of Jacob Clemens non Papa and Vaet's memorial to him, Continuo lachrimas, provides one of the few clues to what may have been an unnatural end to Clemens. Unfortunately, Vaet's extant worklist is nowhere near as extensive as that for Clemens and Lassus; just nine mass settings, two books of motets along with some scattered individual ones, settings of the Salve and Magnificat, nine hymns, and three secular songs.