Matthaeus, Cantacuzenus co-emperor of Constantinople, was the eldest son of the far-more illustrious John V Cantacuzenus (Johannes VI). At twenty-one, four years before he was of age, he was associated by his father in the supreme government as a means of checking the rebellion of John Palaeologus. This measure of Cantacuzenus. however, owing to the popularity of Palaeologus, failed in its design, and in 1355 the associate emperors, father and son, were compelled to abdicate the throne in favor of their rival. Matthaeus now retired with his father to a monastic life in the convents of Mount Athos. He married Irene Palueologina, and became the father of six children. His death, preceding that of his father, occurred towards the end of the 14th century. He was a man of much learning, and the author of various works, mostly Biblical commentaries, several of which are still extant in MS. The one entitled Commentarii in Cantica Canticorun has been published. See Smith, Dict. of Greek and Roman Biography and Mythology, s.v.