Sumer is icumen in

Sumer is icumen in
Canon
Harley MS 978, folio 11v, British Library[1]
Language	Wessex dialect of Middle English

"Sumer is icumen in" is the incipit of a medieval English round or rota of the mid-13th century; it is also known variously as the Summer Canon and the Cuckoo Song.

The line translates approximately to "Summer has come" or "Summer has arrived".^[2] The song is written in the Wessex dialect of Middle English. Although the composer's identity is unknown today, it may have been W. de Wycombe^[3] or a monk at Reading Abbey, John of Fornsete [Wikidata].^[4] The manuscript in which it is preserved was copied between 1261 and 1264.^[3]

This rota is the oldest known musical composition featuring six-part polyphony.^[5]

It is sometimes called the Reading Rota because the earliest known copy of the composition, a manuscript written in mensural notation, was found at Reading Abbey; it was probably not drafted there, however.^[6] The British Library now retains this manuscript.^[7] A copy of the manuscript in stone relief is displayed on the wall of the ruined chapter house of Reading Abbey.^[8]