This term is used to describe music from c500 to c1430. However, as music was not written down until the 9th century and we can only interpret the notation from the 11th century onwards, this earlier boundary is open to debate! The evolution of a reliable method of notating music is perhaps the single most important development in the history of music. Before the 9th century, vocal music was transmitted orally and re-constructed by performers within rules defined by the church. As religious music became more complex, though, it became necessary to record certain elements of it: firstly pitch then later rhythm. However, the oral transmission of music is retained alongside notation throughout this period.
Church music consisted originally of a single line of plainchant, but from the 9th century we know that singing in 2 or more parts was common. This simple form of polyphony was known as ‘Organum’. The extra part(s) would sing the same plainchant at a higher or lower pitch as the original voice, adjusting the melody to avoid the tritone (a dissonance nicknamed ‘the devil in music’!). This style of polyphony reached its zenith in the repertory of Notre Dame composers Leoninus and Pérotinus at the end of the 12th century. Greater freedom in polyphonic writing began to be accepted at the beginning of the 14th century. This was known as ‘ars nova’ or ‘new art’ and is exemplified in the works of Machaut that feature greater independence in part-writing.
The most significant music to come from secular sources are the songs of the Troubadours and, later, the Trouvères. These composer-poets wrote songs that exemplified the notion of ‘courtly love’. For them, to sing and to love were two facets of the same activity. The activities of the Troubadours were at their height from 1180-1220, though the first known Troubadour, William IX Duke of Aquitaine, lived from 1071-1127. Adam de la Halle linked the later Trouvère tradition to the new polyphonic style in the late 13th century, but most of the songs that survive consist only of the words. This period, for both religious and secular music, was thus one of largely oral traditions, though the development of suitable notations was already leading to more complicated music.