Banking originated in India in the late 18th century with the Bank of Hindustan and General Bank of India. The State Bank of India, formed in 1955 from three banks merging in 1921, is the oldest and largest bank still in existence today. Banking in India went through several eras - under colonial rule from the 1820s-1940s, it was primarily private banks. In 1949, the Reserve Bank of India was established and 14 largest commercial banks were nationalized in 1969. Six more banks were nationalized in 1980. Liberalization in the 1990s allowed new private banks to open.