Nigeria's Independence Constitution of 1960 is modelled after the British government. It made Nigeria a Parliamentary monarchy with Dr Nnamdi Azikwe as the Governor-general representing Queen Elizabeth II as the Head of State. Alhaji Tafawa Balewa as the Prime Minister in charge of the day-to-day administration of the country. Nigeria became a Parliamentary Republic in 1963 and then a Republic with a Presidential system in 1979 under Alhaji Shehu Shagari as president.