Complex sentence: Guilford married Jane, his sister Catherine was matched with Henry Hastings, the Earl of Huntingdon's heir, and another Catherine, Jane's sister, married Lord Herbert, the heir of the Earl of Pembroke.
Split into simpler sentences: Guilford married Jane, and his sister Catherine was matched with Henry Hastings, the Earl of Huntingdon's heir. Another Catherine, Jane's sister, was matched with Lord Herbert, the heir of the Earl of Pembroke.