note-against-note embellishments of chants using parallel octaves, fifths, and fourths. Rather than being fixed works, they indicated ways of improvising polyphony during performance. The Winchester Troper, from c. 1000, is the generally considered to be the oldest extant example of notated polyphony for chant performance, although the notation does not indicate precise pitch levels or durations. However, a two-part antiphon to Saint Boniface recently discovered in the British Library, is thought to have originated in a monastery in north-west Germany and has been dated to the early tenth century. European polyphony Historical context European polyphony rose out of melismatic organum, the earliest harmonization of the chant. Twelfth-century composers, such as Léonin and Pérotin developed the organum that was introduced centuries earlier, and also added a third and fourth voice to the now homophonic chant. In the thirteenth century, the chant-based tenor was becoming altered, fragmented, and hidden beneath secular tunes, obscuring the sacred texts as composers continued to play with this new invention called polyphony. The lyrics of love poems might be sung above sacred texts in the form of a trope, or the sacred text might be placed within a familiar secular melody. The oldest surviving piece of six-part music is the English rota Sumer is icumen in (c. 1240). These musical innovations appeared in a greater context of societal change. After the first millennium, European monks started translating Greek philosophy into the vernacular. In the Middle Ages Western Europeans' ignorance of ancient Greek meant they lost touch with works by Plato, Socrates, and Hippocrates. Translations into Latin from Arabic allowed these philosophical works to impact Western Europe. This sparked a number of innovations in medicine, science, art, and music. Western Europe and Roman Catholicism European polyphony rose prior to, and during the period of the Western Schism. Avignon, the seat of popes and then antipopes, was a vigorous center of secular music-making, much of which influenced sacred polyphony. The notion of secular and sacred music merging in the papal court also offended some medieval ears. It gave church music more of a jocular performance quality supplanting the solemnity of worship they were accustomed to. The use of and attitude toward polyphony varied widely in the Avignon court from the beginning to the end of its religious importance in the fourteenth century. Harmony was considered frivolous, impious, lascivious, and an obstruction to the audibility of the words. Instruments, as