Chief of Army Staff or COAS is the highest post in the Pakistani army and is held by a senior officer of 4 star rank. Under the 1973’s constitution of Pakistan, the COAS is under the authority of the civilian leadership and reports directly to the president, prime minister, defence minister and the defence secretary of Pakistan.
Before the 1973 constitution, the COAS were referred to as Army Commander-in-Chief. There were six Commanders-in-Chief namely General Sir Frank Messervy (15TH Aug 1947 to 10th Feb 1948), General Sir Douglas Gracey (11th Feb 1948-16th Jan 1951), Field Marshal Muhammad Ayub Khan (16th Jan 1951-26th Oct 1958), General Muhammad Musa (27th October 1958-17th June 1966), General Agha Muhammad Yahya Khan(18th June1966-20th Dec 1971), Lieutenant General Gul Hassan Khan (20th Dec 1971-3rd March 1972).
Among these Commanders-in-Chief, Field Marshal Ayub Khan and Yahya Khan overthrew the elected governments and declared martial law. Ayub Khan later became the president and remained on the post for almost a decade.
From 1973 onwards the Commander-in-Chief was replaced by COAS; the first COAS was General Tikka Khan (3rd March 1972-1st March 1976), General Muhammad Zia-ul-Haq (1st March 1976-17th August 1988), General Mirza Aslam Beg (17th August 1988- 16th August 1991), General Asif Nawaz (16th August 1991-8th Jan 1993), General Abdul Waheed (11th Jan 1993-12th Jan 1996), General Jehangir Karamat (12th Jan 1996- 6th Oct 1998), General Pervez Musharraf (6th Oct 1998-Nov 28th 2007) and General Ashfaq Kiyani (29th Nov 2007-present).
General Zia ul Haq also declared martial law by overthrowing the elected government of Zulfiqar Ali Bhutto in 1977. Zia ul Haq proceeded to become the president; he even held elections on no party basis and brought his puppet government in power. For eleven years he held the posts of both the COAS and the President until he died in a plane crash in 1988.
General Pervez Musharraf too declared emergency in 1998 and removed the elected government of Nawaz Sharif from power. For nine years he ruled overPakistanas the president while refusing to surrender his army uniform which he called his second skin. Then in 2007 on the insistence of almost the whole nation he gave up his army post. After Gen Musharraff, General Kayani served as COAS. After General Kiyani’s retirement, General Raheel Shareef took over the charge, in 2013.