Complex sentence: The Satna District is part of the region of Bagelkhand, of which a large part was ruled by the state of Rewa and a small part was ruled by feudatory chiefs, holding their states under the British Raj.
Split into simpler sentences: The Satna District is part of the region of Bagelkhand, a large part of which was ruled by the state of Rewa. A small part of Satna was ruled by feudatory chiefs, holding their states under the British Raj.