The chief architect of Partition of India who oversaw the the defeat of the Japanese offensive towards India during WW II he was appointed the last Viceroy of British India and first Governor general of Independent India.
In March 1947, Mountbatten became th Viceroy of India.with a mandate to oversee the British withdrawal . He established good relations with leading politicians, particularly with Jawaharlal Nehru, but was unable to persuade the Muslim leader M.A.Jinnahof the benefits of a United India.
Mountbatten,ultimately, gave up hope of a united country and on 14-15 Aug 1947, British India was partitioned into the two staes.
After long Colonial period India got half hearted independence from Great Britain. The partition of British India was done on the basis of religious demographics that led to the creation of Pakistan (later Islamic Republic of Pakistan and People's Republic of Bangladesh) on 14th Aug 1947 and 15th Aug 1947 the Union of India (later Republic of India).Mountbatten remained as Interim Governor General of India until June 1948. For his services during the war and in India, he was created Viscount in 1946 and Earl Mountbatten of Burma the following.
The two nation theory, on the basis of which India was divided proved baseless when Bangladesh was separated from Pakistan.