The island is mainly known as the site of a Benedictine nunnery, later a Franciscan convent.
There was a Benedictine nunnery here from its foundation in 1126, by Archbishop Frederick I of Cologne and Abbot Kuno of Siegburg. In 1465 it joined the reform movement of the Bursfelde Congregation, but was severely damaged in 1477 during hostilities with Burgundy. It also suffered greatly from marauding Swedish troops in 1632, during the Thirty Years' War.
In 1773 it was destroyed by fire, and rebuilt in the Baroque style. In 1802 the nunnery was dissolved as part of the secularisation of ecclesiastical property. In 1821 the premises were sold by auction and used as an inn. This was visited by Franz Liszt, who composed the piece "Die Zelle in Nonnenwerth" about it.
In 1854 the buildings were acquired by the Franciscans for a convent. During World War I the sisters began to teach girls and a secondary school soon developed, still in operation.