(B) The bank descends from the Bank of Calcutta, founded in 1806, via the Imperial Bank of India, making it the oldest commercial bank in the Indian subcontinent. The Bank of Madras merged into the other two ‘presidency banks’ in British India, the Bank of Calcutta and the Bank of Bombay, to form the Imperial Bank of India, which, in turn,became the State Bank of India in 1955. The Government of India took control of the Imperial Bank of India in 1955,with Reserve Bank of India(India’s central bank) taking a 60% stake, renaming it the State Bank of India.