The history of Manipur (Kangleipak in ancient times) is reflected by archaeological research, mythology and written history. Starting from the origin of Polo (Meitei: Sagol Kangjei) in 3100 BC, Manipur became a princely state under British rule in 1891, the last of the independent states to be incorporated into British India. During the Second World War, Manipur was the scene of battles between Japanese and Allied forces. After the war, Maharaja Bodhachandra signed a Treaty of Accession merging the kingdom into India. It was made a union territory in 1956 and a full-fledged state in 1972.