Complex sentence: Matthias sent reinforcements under the command of Blaise Magyar, Voivode of Transylvania, to Stephen the Great who routed the invaders in the Battle of Vaslui on 10 January 1475.
Split into simpler sentences: Matthias sent reinforcements under the command of Blaise Magyar to Stephen the Great. Their united forces routed the invaders in the Battle of Vaslui on 10 January 1475.