This book deals with the spiritual identity of the nuns of the Heiningen Convent in Lower Saxony in the middle of the 15th century. It is based on a group of manuscripts written during the Windesheim reform of the convent which established the textual basis of spiritual care and the new liturgical practices. The novices’ initiation liturgy and profession including the chants (with notations) is edited and illustrated here for the first time and studied in the context of the nuns’ education and way of life.