After gaining independence from the British in 1947, the State of Pakistan was physically separated into two exclaves, with the western and eastern wings separated from each other by the Republic of India. The western wing of Pakistan comprised three Governor's provinces (North-West Frontier, West-Punjab and Sindh Province), one Chief Commissioner's province (Baluchistan Province), and the Baluchistan States Union along with several other independent princely states (notably Bahawalpur, Chitral, Dir, Hunza, Khairpur and Swat), the Federal Capital Territory around Karachi, and the tribal areas.[1] The eastern wing of the new country – East Pakistan – formed the single province of East Bengal (including the former Assam district of Sylhet).
West Pakistan was politically dominant despite East Pakistan having over half of the population and a disproportionately small number of seats in the Constituent Assembly. This inequality of the two wings and the geographical distance between them were believed to be delaying the adoption of a new constitution. To diminish the differences between the two regions, the government decided to reorganise the country into two distinct provinces under the One Unit policy announced by Prime Minister Chaudhry Muhammad Ali on 22 November 1954.
In 1970, President General Yahya Khan enacted a series of territorial, constitutional and military reforms. These established the provincial assemblies, state parliament, and the current provisional borders of Pakistan's four provinces. On 1 July 1970, West Pakistan was devolved and renamed "Pakistan" under Legal Framework Order No. 1970, which dissolved the "One Unit" and removed the term "West", simply establishing the country as Pakistan.[1] The order had no effect on East Pakistan, which retained the geographical position established in 1955.[1] The next year's civil war, however, resulted in the secession of East Pakistan as the new country of Bangladesh.