In 1184, Walter gave his support to the marriage of Constance, daughter of Roger II, with Henry, son of Frederick Barbarossa. He was one of the only ones, for Constance, as the only legitimate heir to the throne, was long confined to a monastery due to a prophecy that "her marriage would destroy Sicily". Although he supported Constance to succeed William II, at the request of Pope Clement III, he had to crown Tancred of Lecce king in his cathedral in early January 1190. He died of natural causes early in 1191 and was buried in his rebuilt cathedral. Besides the cathedral, reworked so many times over the centuries, Walter left as architectural nods to his patronage of the arts the chapels of Santa Cristina and Santo Spirito. The latter is the "church of the Vespers," the church in front of which the first insult and the first murder of the Sicilian Vespers took place in 1282.