One type of melody is called the cantus firmus from which other melodies or voices were derived. A composer often based the melody he wrote for other parts on the cantus firmus. Cantus firmus was commonly used in the Middle Ages and was strongly based on the Gregorian Chant.
Motet emerged in Paris around the year 1200. It is a type of polyphonic vocal music which uses rhythm patterns. Early motets were both sacred and secular; touching on subjects like love, politics and religion. It flourished until the 1700s and today is still being used by the Catholic Church.
A round is a vocal piece wherein different voices sing the same melody, at the same pitch, but the lines are successively sung. An early example of a round is Sumer is icumen in, a piece that is also an example of a six-voice polyphony. The children's song "Row, Row, Row Your Boat" is an example of a round.
The Role of Ministrels, Troubadours and Minnesingers
Ministrels, also called jongleurs, were traveling musicians and jugglers who performed in streets and courts during the 11th and 12th centuries. Their works represent the early forms of secular music. Troubadours on the other hand were French musicians and poets who wrote courtly love poems and set it to music. They performed their songs in European courts and throughout the country. Eventually their popularity reached and flourished in Germany during the 12th and 13th centuries where they became known as minnesingers. These performers helped spread vocal music which later evolved into other forms.