In the spring of 1260, he was at either at Nicaea or at Nicles in the Peloponnese; in the autumn of the same year, he was at Thebes, where the Dominicans had been since 1253 and where he dated his translation of Aristotle's De partibus animalium.
Then, from 1278 until his death in 1286 (which probably occurred several months before the nomination of his successor as bishop in October 1286), he occupied the Latin Archbishopric of Corinth, a Catholic see established in the northeastern Peloponnese after the Fourth Crusade.
He was associated with the philosopher Thomas Aquinas, the mathematician John Campanus, the Silesian naturalist and physician Witelo, and the astronomer Henri Bate of Mechlin, who dedicated to William his treatise on the astrolabe.
A little Greek village, Merbaka, with an exceptional late-13th-century church, is believed to have been named for him[citation needed]; it lies between Argos and Mycenae.
In Umberto Eco's puzzle-mystery set in the 1320s, The Name of the Rose, there is some debate among the monks about Aristotle's Poetics (Second Day: Prime).