Bank of Calcutta:
The Bank of Calcutta (a precursor to the present State Bank of India) was founded on 2 June 1806, mainly to fund General Wellesley’s wars against Tipu Sultan and the Marathas. It was the first bank of India and was renamed Bank of Bengal on 2 January 1809.
Bank of Bombay:
Bank of Bombay was the second of the three presidency banks (others being the Bank of Calcutta and the Bank of Madras) of the Raj period. It was established, pursuant to a charter of the British East India Company, on 15 April 1840.
Bank of Madras:
The Bank of Madras was one of the three Presidency Banks of British India, along with the Bank of Bengal and the Bank of Bombay. It was established on 1 July 1843 through the amalgamation of a number of existing regional banks and headquartered in Madras (now Chennai). The Bank of Calcutta, and the two other Presidency banks — the Bank of Bombay and the Bank of Madras — amalgamated on 27 January 1921 and the reorganized banking entity assumed the name Imperial Bank of India. The Reserve Bank of India, which is the central banking organization of India, in the year 1955, acquired a controlling interest in the Imperial Bank of India and the Imperial Bank of India was renamed on 30 April 1955 as the State Bank of India.