The Iran-Iraq War (also called the First Persian Gulf War, or the Imposed War in Iran) was a war between the Republic of Iraq and the Islamic Republic of Iran that lasted from September 22, 1980, until August 20, 1988.

The conflict saw early successes by the Iraqis, but soon after they were repulsed and the conflict stabilized into a long war of attrition. It was commonly referred to as the Persian Gulf War until the Iraq-Kuwait conflict (1990-91), which became known as the Second Persian Gulf War and later simply the Persian Gulf War.

The origins of the war are disputed, but it was fundamentally a war over dominance in the Persian Gulf region. The destabilization of Iran and its alienation from the West made that country a tempting target to the ambitious Saddam Hussein, Iraq’s President. There were a number of outstanding territorial disputes between the two powers. One of the factors contributing to hostility between the two powers was Saddam Hussein’s desire to regain full control of the Shatt al-Arab waterway at the head of the Persian Gulf, an important channel for the oil exports of both countries. In 1975, United States Secretary of State Henry Kissinger had sanctioned that Mohammad Reza Pahlavi, the Shah of Iran, attack Iraq over the waterway, which was under Iraqi control at the time; soon after both nations signed the Algiers Accord, in which Iraq made territorial concessions, including the waterway, in exchange for normalized relations. Iraq also had designs on the Iranian province of Khuzestan, which is one of the main oil-rich areas in Iran.

Saddam had recently come to power and was interested in elevating Iraq to a strong regional power. A successful invasion of western Iran would make Iraq the dominating force in the Persian Gulf region and its lucrative oil trade. Such lofty ambitions were not that far-fetched. Severe officer purges (including several executions ordered by Sadegh Khalkhali, the post-revolution Sharia ruler) and spare part shortages for Iran’s American-made equipment had crippled Iran’s once mighty military. The bulk of the Iranian military was made up of poorly armed, but committed, militias. Iran also had minimal defenses in the Arvand/Shatt al-Arab river.

The aftermath of the Iranian Revolution of 1979 was also central to the conflict. Iran was threatening to spread its revolution. It was widely believed that the oppressed Shi’ites in Iraq, Saudi Arabia, and Kuwait could follow the Iranian example and turn against their governments. The Iranians had been supporting Kurdish separatists in northern Iraq, and Shi’ite leaders in the rest of the country.

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