Afghanistan's name is derived from an old word for "camp" or "fort". The name was first used in the 17th century, by the Mughal Empire. Afghanistan was part of the Muslim world and a centre of Islamic scholarship. During the 19th and early 20th centuries, it was one of the most important centres of political activity and education in Central Asia. In 1919, Afghanistan became a republic within the First World War-era Middle Eastern Coalition. It maintained close relations with both Russia and Great Britain, but sided with the Soviet Union during the Cold War. Following the Soviet withdrawal from Afghanistan in 1989, civil wars broke out between various Afghan factions. In September 2001, U.S.-led forces invaded Afghanistan to overthrow the Taliban government and disrupt al-Qaeda operations there. The United States now occupies much of that country, as do several other NATO countries.