Rota
A rota is a type of round, which in turn is a kind of partsong. To perform the round, one singer begins the song, and a second starts singing the beginning again just as the first got to the point marked with the red cross in the first figure below. The length between the start and the cross corresponds to the modern notion of a bar, and the main verse comprises six phrases spread over twelve such bars. In addition, there are two lines marked "Pes", two bars each, that are meant to be sung together repeatedly underneath the main verse. These instructions are included (in Latin) in the manuscript itself.
"Sumer Is Icumen In" in modern notation:
Read more about this topic: Sumer Is Icumen In