Sumer Is Icumen In is the oldest known counterpoint song, written 1240.
Sumer Is Icumen In
Sumer is a-coming in,
Loudly sing, cuckoo!
Groweth seed and bloweth mead
And springeth wood anew.
Sing, cuckoo!
Sing, cuckoo! Sing, cuckoo! Sing, cuckoo! 
KOMOS
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