Complex sentence: Thomas revives, and it turns out that Thomas is the Duke of Islington and that he had disguised himself as a commoner so that he could search for a humble, virtuous wife without revealing his true rank.
Split into simpler sentences: Thomas revives, and it turns out that he is the Duke of Islington. He had disguised himself as a commoner so that he could search for a humble, virtuous wife without revealing his true rank.