Complex sentence: Matthias Corvinus gave Jusztina into marriage to Wenceslas (also known as Ladislaus) Pongrác of Szentmiklós, a member of an influential noble family which owned estates in Upper Hungary (now Slovakia).
Split into simpler sentences: Matthias Corvinus gave Jusztina into marriage to Wenceslas (also known as Ladislaus) Pongrác of Szentmiklós. He was a member of an influential noble family which owned estates in Upper Hungary (now Slovakia).