The Khanate of Kalat, which covered the substantial area of 139,850 km2 (53,995 sq mi), was reported in 1951 to have a population of 253,305. It remained fully independent from 15 August 1947 until 27 March 1948, when its ruler, Ahmad Yar Khan (1904–1979), finally acceded to Pakistan. On 3 October 1952 the state of Kalat entered into the Baluchistan States Union with three neighbouring states, Kharan, Las Bela, and Makran, with the Khan of Kalat at the head of the Union with the title of Khan-e-Azam. The Khanate came to an end on 14 October 1955, when it was incorporated into West Pakistan.
On 20 June 1958, Mir Sir Ahmad Yar Khan Ahmedzai, the Khan of Kalat, declared Baluchistan independent. On 6 October 1958, the Balochistan police captured the Kalat Palace and arrested the Khan for sedition. The next day, Iskandar Mirza declared martial law, which led to disturbances in Balochistan lasting about a year. The Khan was eventually forgiven and released.