W. Aleyn is certified as the author of a Gloria (OH No. 8) and an Agnus Dei (OH No. 128) in the Older Hall Manuscript. The name can be mounted on a contrafacta establishing in the dropped Strasbourg manuscript copied by Coussemaker in 1866, C. 222. As many of the items in C. 222 are acknowledged to Johannes Alanus, also called “John Aleyn,” scholars once assumed that “Aleyn” and Alanus had been one as well as the same. But an X-ray study of the Aged Hall Manuscript reveals the name “Aleyn” is definitely prefixed by a short that are a notice W, indicating a completely different composer is definitely represented. If therefore, W. Aleyn was an British composer likely energetic in a period contemporaneous towards the Aged Hall Manuscript, maybe in the 1420s, instead of from enough time of Alanus, who passed away in 1373.