Iran was directly involved in war with Iraq (1980-1988) – which is also known as the First Persian Gulf War and by various other names. It was an armed conflict between the armed forces of Iraq and Iran, lasting from September 1980 to August 1988, making it the longest conventional war of the 20th century.
The war began when Iraq invaded Iran, launching a simultaneous invasion by air and land into Iranian territory on 22 September 1980 following a long history of border disputes, and fears of Shia Islam insurgency among Iraq’s long-suppressed Shia majority influenced by the Iranian Revolution.
Iraq was also aiming to replace Iran as the dominant Persian Gulf state. Although Iraq hoped to take advantage of the revolutionary chaos in Iran and attacked without formal warning, they made only limited progress into Iran and were quickly repelled by the Iranians who regained virtually all lost territory by June 1982. For the next six years, Iran was on the offensive.
The war came at a great cost in lives and economic damage—half a million Iraqi and Iranian soldiers as well as civilians are believed to have died in the war with many more injured—but it brought neither reparations nor change in borders.
The conflict is often compared to World War I, in that the tactics used closely mirrored those of that conflict, including large scale trench warfare, manned machine-gun posts, bayonet charges, use of barbed wire across trenches, human wave attacks across no-man’s land, and extensive use of chemical weapons such as mustard gas by the Iraqi government against Iranian troops and civilians as well as Iraqi Kurds.
The war was commonly referred to as the Gulf War or Persian Gulf War until the Iraq-Kuwait conflict (Jan–Feb 1991), and for a while thereafter as the First Persian Gulf War. The Iraq-Kuwait conflict, while originally known as the Second Persian Gulf War, later became known simply as the “Gulf War”. The United States-led invasion of Iraq in 2003 and the following occupation of the country from 2003–2011 has since been called the “Second Persian Gulf War”.