My Next Medieval Guitar Hymn

My next guitar project is trying to learn another medieval Christmas hymn from as close to my 12th century persona period as possible. For Sergeant's Trials, I performed "What Child is This" also known as Greensleeves, along with O Come Emmanuel and While Shepherds Watched Their Flocks by Night. Next on the list will be an attempt to learn "Infant Holy, Infant Lowly".