Complex sentence: Otto III, Duke of Bavaria became Bela V of Hungary, taking the name of his maternal grandfather, Béla IV of Hungary, and Wenceslaus III of Bohemia signed his royal documents in Hungary as Ladislas, being this a very traditional name in the Kingdom.
Split into simpler sentences: Otto III, Duke of Bavaria became Bela V of Hungary, taking the name of his maternal grandfather, Béla IV of Hungary. In the other hand, Wenceslaus III of Bohemia signed his royal documents in Hungary as Ladislas, being this a very traditional name in the Kingdom.