At midnight on August 15th, 1947, Pakistan was created. With the Indian Independence Act of 1947, the release of control by the British would also split what was known as British India into two distinct countries whose borders were determined by the religious groups that most densely populated the areas. The Union of India (later Republic of India) would be secular but with a Hindu majority and Muslims would control the Dominion of Pakistan (later divided further still into Pakistan and Bangladesh.) The states of Bengal and Punjab were also sliced in two along the Radcliffe Line, as well as the Army, Treasury, Navy, and Railway industry.
Muhammad Ali Jinnah, who is regarded as the father of Pakistan, believed that a unified nation would only lead to marginalization of Muslims and, eventually, violence and civil war.
However, the division of the country led to the displacement of millions of people. Hindus and Muslims who suddenly found themselves in different countries on August 15th fled their home in fear of violence.