In the Muslim Middle East, a military commander, governor of a province, or high military official. The first leader to call himself emir was the second caliph, Umar ibn al-Khattab. The title was used by all his successors until the abolition of the caliphate in 1924. In the 10th century the commander of the caliph's armies at Baghdad held the title. It was later adopted by the rulers of independent states in central Asia, notably Bukhara and Afghanistan. The United Arab Emirates, despite their name, are all ruled by sheikhs.