The office of amir al-umara (Arabic: أمير الأمراء, amīr al-umarāʾ), variously rendered in English as emir of emirs,chief emir, and commander of commanders, was a senior military title in the 10th-century Abbasid Caliphate, whose holders in the decade after 936 came to supersede the civilian bureaucracy under the vizier and become effective regents, relegating the caliphs to a purely ceremonial role. The office then formed the basis for the Buyid control over the Abbasid caliphs and Iraq after 946.
The title continued in use by Muslim states in the Middle East, but was mostly restricted to senior military leaders. It was also used in Norman Sicily for a few of the king's chief ministers.
The first person to be titled amir al-umara was the commander Harun ibn Gharib, a cousin of the Caliph al-Muqtadir (r. 908–932), in 928. He was followed soon after by his rival, the eunuch Mu'nis al-Muzaffar (845–933), who served as commander-in-chief of the caliphal army and the power behind the throne for most of al-Muqtadir's reign. From 928, Mu'nis was involved in a tumultuous power struggle with his rivals in the court's civilian bureaucracy, which ended with the deposition and execution of al-Muqtadir in 932, and his replacement with his brother al-Qahir (r. 932–934). Mu'nis and the military were now dominant in the affairs of the Abbasid court, beginning a period of troubles that was, in the words of the historian Hugh Kennedy, "dominated by the struggles of military men to control the caliphate and, perhaps more importantly, the revenues of the Sawad which would enable them to satisfy the demands of their followers".
Mu'nis himself was executed by al-Qahir in 933, but in 934 another palace coup deposed al-Qahir and replaced him with ar-Radi (r. 934–940). The frequent coups and violent struggle for control of the Caliphate greatly enfeebled the central government in Baghdad. Effective control over the Maghreb and Khurasan had long been lost, but now autonomous rulers emerged in the provinces closer to Iraq: Egypt and Bilad al-Sham were ruled by the Ikhshidid dynasty, the Hamdanid dynasty had secured control over Upper Mesopotamia, and most of Iran was ruled by Daylamite dynasties, among whom the Buyids were most prominent. Even in Iraq itself, the authority of the caliphal government was challenged. Thus in the south, around Basra, Abu Abdallah al-Baridi established his own domain, often refusing to send tax revenues to Baghdad and establishing contacts with the Buyids of nearby Fars. The historian Ali ibn al-Athir (d. 1233) asserted that after the death of Mu'nis, the post of amir al-umara fell to Tarif al-Subkari, who was also head of the treasury.