Complex sentence: Within the sacristy, a large, dark painting of the crucifixion that is commonly attributed to the Dutch artist, Anthony Van Dyck, despite the claims of some local guides who believe it is the work of the Spanish Alonso Cano, from the 17th century.
Split into simpler sentences: Within the sacristy, a large, dark painting of the crucifixion is commonly attributed to the Dutch artist, Anthony Van Dyck. Some local guides say it is the work of the Spanish artist Alonso Cano, from the 17th century.