I've very kindly been asked to post this on 'The Trees They Do Grow High' thread, so ...

The music of the 13th century English song, 'Sumer is icumen in', one of the earliest surviving songs in English, was doctored by the scribe, thus erasing the most joyful part of the melody, argues a new article. The motivation lay in the devotional song it was paired with, 'Perspice Christicola'. The article includes videos of both songs ('Sumer' in a folk club, with the audience singing the ground bass), supporting evidence from the manuscript, and a reconstruction and analysis of the original 'Sumer' melody.