The Online Thematic Catalogue of Lully Keyboard Arrangements (OTCL) provides the first digitized catalogue of over 600 pieces from some 70 manuscript and printed sources that constitute the repertory of keyboard arrangements of Jean-Baptiste Lully’s music. As many scholars have remarked, arrangements, in particular those of Lully’s music, are an integral part of seventeenth-century French harpsichord music. By bringing together information on original sources, modern editions and facsimile editions and the latest research and by making this information searchable, OTCL aims to facilitate research into and performance of this repertory.