Mujahideen (Arabic: المجاهدين literally meaning someone who is involved in Jihad) are a guerilla-combat style military force. Formed during the Cold War-era Afghan-Soviet war, they were initially several loosely-related Afghan rebel groups.
Whilst the modern definition of mujahideen considers the Afghan war to be the birth of modern muhajideen, the history goes back to the 19th century.
During the 1970s, Afghanistan was ruled by the communist Democratic Republic of Afghanistan (DRA), a pro-Soviet government. A coalition of loosely-affiliated groups, the mujahideen were opposed to their government’s allowance of the USSR to bring Soviet forces into Afghanistan to assist the Russians.As the warfare continued, mujahideen organization grew and changed from a decentralized, fractured coalition of groups fighting local battles into the Islamic Unity of Afghanistan Mujahideen. Muslims from around the world poured into Afghanistan and the neighboring countries prepared to fight against the Russians, widening the skill set of the ever-expanding mujahideen and often bringing money to the cause.
Keen to drag the Soviet’s into their own version of Vietnam and to prevent absorption of Afghanistan into the USSR, the Americans trained, equipped and funded the mujahideen through the CIA via the Pakistani ISI, in an operation called Operation CYCLONE. Hoping that the long drawn-out war would variously distract and damage the USSR, the American investment was hoped to result in severe economic and military damage to the Soviet regime.
Once the Afghan-Soviet war ended, the various factions making up the mujahideen dissolved and re-assimilated back into several groups, many using the training and weapons received by the CIA and ISI to practice terrorism on a global scale (Osama bin Laden was the most famous CIA-sponsored mujahideen commander).