Complex sentence: Mary was one of the mistresses of Henry VIII. It has been rumoured that she bore two of the king's children, though Henry did not acknowledge either of them as he had done with Henry FitzRoy, his son by Bessie Blount.
Split into simpler sentences: Mary was one of the mistresses of Henry VIII. It has been rumoured that she bore two of the king's children, though Henry did not acknowledge either of them. Unlike he had done with Henry FitzRoy, his son by Bessie Blount.