Complex sentence: Matthew Kantakouzenos or Cantacuzenus (Greek: Ματθαίος Ασάνης Καντακουζηνός, "Matthaios Asanēs Kantakouzēnos", c.1325-1383 or 1391) was Byzantine Emperor from 1353 to 1357.
Split into simpler sentences: Matthew Kantakouzenos or Cantacuzenus (Greek: Ματθαίος Ασάνης Καντακουζηνός, "Matthaios Asanēs Kantakouzēnos") (c.1325--1383 or 1391). He was Byzantine Emperor from 1353 to 1357.