Complex sentence: The name of Tykocin was first mentioned in the 11th century and through the 14th century it was a Duchy of Masovian castellany seat and castle on the Masovian border neighboring the growing medieval pagan Lithuania.
Split into simpler sentences: The name of Tykocin was first mentioned in the 11th century. Through the 14th century it was a Duchy of Masovian castellany seat and castle on the Masovian border neighboring the growing medieval pagan Lithuania.