Manipur, known as 'Meetei Leipak' or 'Kangleipak' in the two millennia old Meetei manuscripts had experienced some form of constitutional government under a proto-Constitution in 429 A.D. which was reduced to a final format in 1110 A.D. Constitution entitled 'Loiyamba Shinyeri' during the regime of King Loyumba, Manipur's State Constitution Act, 1947 was the final document embodying the genius of the people of Manipur, which preceded other constitutions adopted in many of the South and South East Asian countries. Manipur's love hate and war relationship with Britain commenced with a treaty in 1762 and was put to test in two successive Anglo-Manipur wars in 1891, which created storm in British Public opinion in Britain. The Times and The Daily News of London poured in the events continuously to the British public. The debate in British Parliament covered more than 200 pages on Manipur. The native rule under the limited protection of the crown was continued. Manipur merged with newly born Indian Union in 1949. The selected treaties and historical documents will enlighten some of the obscure events in the history of Manipur.