Complex sentence: He married Lady Catherine Howard (b. abt 1499 Ashwellthorpe, Norfolk, England), the daughter of Thomas Howard, 2nd Duke of Norfolk and Agnes Tilney.
Split into simpler sentences: He married Lady Katherine Howard (b. abt 1499 Ashwellthorpe, Norfolk, England). She was the daughter of Thomas Howard 2nd Duke of Norfolk and Agnes Tilney.