Accounting for 80 of the Lok Sabha’s 543 seats, and a 403-member Assembly, Uttar Pradesh, with its over 15 crore voters, is India’s most politically significant state. Since January 25, 1950, when the United Provinces was renamed as Uttar Pradesh, the state – through 17 Assembly elections -- has determined the course of national politics, throwing up a legion of stalwarts, chief ministers, and Prime Ministers. Of its 21 CMs though, only Yogi Adityanath, Akhilesh Yadav and Mayawati have completed a full five-year term, reflecting the intense volatility of its politics. In the line-up of CMs, also lies the truth about the state's caste equations. Ten of its 21 CMs have been Brahmins or Thakurs. The remaining include three Yadavs, three Baniyas, one Lodh, one Jat, one Kayasth, one Dalit and one Sindhi. A series looking at UP's political history and changes through its CMs.