Flemish by origin, and a Dominican by vocation, eventually he was made bishop of Corinth. He held intellectual intercourse with the philosopher Thomas Aquinas, the mathematician John Campanus, the Polish naturalist and physician Witelo, and the astronomer Henri Bate of Mechlin, who dedicated to William his treatise on the astrolabe.
In turn he resided at the pontifical court of Viterbo (1268), appeared at the Council of Lyons (1274), and from 1277 until his death occupied the See of Corinth, a Catholic bishopric established in the Argolis (Greece) after the Fourth Crusade. A little Greek village named for him, Merbaka (Agia Triada), lies between Argos and Mycenae.
At the request of Thomas Aquinas he undertook a complete translation of the works of Aristotle or, for some portions, a revision of existing translations. He was the first translator of the Politics (c. 1260). The reason for the request was that the copies of Aristotle in Latin then in circulation had originated in Spain (see Gerard of Cremona), from the Arabic schools of the rationalist Averroes whose texts had passed through Syriac versions before being re-translated into Arabic. Aristotle was madeto be a source of philosophical and theological errors. The translations have had a long history. They were already standard classics by the 14th century, when Henricus Hervodius put his finger on their enduring value: they were literal (de verbo in verbo), faithful to the spirit of Aristotle and without elegance. For several of William's translations, the Greek texts have since disappeared: without him the works would be lost.
In Umberto Eco's puzzle-mystery set in the later 13th century, The Name of the Rose, there is some debate among the monks about Aristotle's Poetics. (Second Day: Prime) Jorge of Burgos has condemned this book because knowledge of it came through the "infidel Moors" (as so much of Aristotle had indeed come). But the main character, William of Baskerville, knew that Aristotle's Poetics had recently been translated directly from Greek into Latin by William of Moerbeke.
William also translated mathematical treatises by Hero of Alexandria and Archimedes. Especially important was his translation of the Theological Elements of Proclus (made in 1268), because the Theological Elements is one of the fundamental sources of the revived Neo-Platonic philosophical currenys of the 13th Century.
The Vatican collection holds William's own copy of the translation he made of the greatest Hellenistic mathematician, Archimedes, with commentaries of Eutocius, which was made in 1269 at the papal court in Viterbo. William consulted two of the best Greek manuscripts of Archimedes, both of which have since disappeared. The manuscript, in his own hand, was in the exhibition "Rome Reborn: The Vatican Library & Renaissance Culture" at the Lib. of Congress.