Watch on Soap2day. Artus - Excalibur is a musical loosely based on the legends of the 5th/6th-century British monarch King Arthur and his fabled sword, Excalibur. The score is by Frank Wildhorn, with lyrics by Robin Lerner and book by Ivan Menchell. The musical had its world premiere at the Theater St. Gallen in St. Gallen, Switzerland in 2014