Complex sentence: Seymour was married before 1500 to Margery Wentworth, who was the daughter of Sir Henry Wentworth of Nettlestead, Suffolk, and his wife Anne Say.
Split into simpler sentences: Seymour was married before 1500 to Margery Wentworth. As the daughter of Sir Henry Wentworth of Nettlestead, Suffolk, and his wife Anne Say.