The Iran–Iraq War was an armed conflict between the Islamic Republic of Iran and the Iraqi Republic lasting from September 1980 to August 1988, making it the 20th century's longest conventional war.
The Iran–Iraq War began when Iraq invaded Iran via air and land on 22 September 1980. It followed a long history of border disputes, and was motivated by fears that the Iranian Revolution in 1979 would inspire insurgency among Iraq's long-suppressed Shia majority, as well as Iraq's desire to replace Iran as the dominant Persian Gulf state. Although Iraq hoped to take advantage of Iran's revolutionary chaos and attacked without formal warning, it made only limited progress into Iran and was quickly repelled; Iran regained virtually all lost territory by June 1982. For the next six years, Iran was on the offensive. A number of proxy forces participated in the war, most notably the Iranian Mujahedin-e-Khalq siding with Ba'athist Iraq and Iraqi Kurdish militias of Kurdistan Democratic Party and Patriotic Union of Kurdistan siding with Iran—all suffering a major blow by the end of the conflict.
Despite calls for a ceasefire by the United Nations Security Council, hostilities continued until 20 August 1988. The war finally ended with Resolution 598, a U.N.-brokered ceasefire which was accepted by both sides. At the war's conclusion, it took several weeks for Iranian armed forces to evacuate Iraqi territory to honour pre-war international borders set by the 1975 Algiers Agreement. The last prisoners of war were exchanged in 2003. (Full article...)