Complex sentence: The 36 royal races ("Chathis Rajkula ") was a listing of royal clans of Rajasthan by Colonel James Tod in his 1829 work"Annals and Antiquities of Rajasthan" (volume 1).
Split into simpler sentences: The 36 royal races ("Chathis Rajkula ") is a listing of Indian social groups purported to be the ruling clans of Rajasthan. A listing of the 36 was attempted by Tod in his 1829 work"Annals and Antiquities of Rajasthan" (volume 1).