Parchment bifolium containing a part of the 9th century treatise on music theory Musica enchiriadis. While it was attributed to the Benedictine monk Hucbald for a long time, today it is considered the work of an anonymous author. The bifolium was used as binding for the Liber Cellae sub littera V, with accounts from 1526 to 1528 from the collegiate church of St. Leodegar in Schönenwerd.