East Pakistan was renamed from East Bengal by the One Unit scheme of Pakistani Prime Minister Mohammad Ali of Bogra . The Constitution of Pakistan of 1956 replaced the British monarchy with an Islamic republic . Bengali politician H. S. Suhrawardy served as the Prime Minister of Pakistan between 1956 and 1957 and a Bengali bureaucrat Iskandar Mirza became the first President of Pakistan . The 1958 Pakistani coup d'état brought general Ayub Khan to power . Khan replaced Mirza as president and launched a crackdown against pro-democracy leaders . Khan enacted the Constitution of Pakistan of 1962 which ended universal suffrage . By 1966 , Sheikh Mujibur Rahman emerged as the preeminent opposition leader in Pakistan and launched the six point movement for autonomy and democracy . The 1969 uprising in East Pakistan contributed to Ayub Khan 's overthrow . Another general , Yahya Khan , usurped the presidency and enacted martial law . in 1970 , Yahya Khan organized Pakistan 's first federal general election . The Awami League emerged as the single largest party , followed by the Pakistan Peoples Party . The military junta stalled in accepting the results , leading to civil disobedience , the Bangladesh Liberation War and the 1971 Bangladesh genocide . East Pakistan seceded with the help of India
1971 Bangladesh genocide
1971 Bangladesh genocide
East Pakistan