The colonial era Hindu revivalism and mobilisation, along with Hindu nationalism, states Peter van der Veer, was primarily a reaction to and competition with Muslim separatism and Muslim nationalism. The successes of each side fed the fears of the other, leading to the growth of Hindu nationalism and Muslim nationalism in the Indian subcontinent. In the 20th century, the sense of religious nationalism grew in India, states van der Veer, but only Muslim nationalism succeeded with the formation of the West and East Pakistan (later split into Pakistan and Bangladesh), as "an Islamic state" upon independence. Religious riots and social trauma followed as millions of Hindus, Jains, Buddhists and Sikhs moved out of the newly created Islamic states and resettled into the Hindu-majority post-British India. After the separation of India and Pakistan in 1947, the Hindu nationalism movement developed the concept of Hindutva in second half of the 20th century.