"Not equal are those of the believers who stay home without any proper excuse and those who strive hard and fight in the cause of Allah with their wealth and their lives." — The Qur'an, 4:95 First introduced by the caliph al-Muwaffaqin the late 9th century CE, the Mamluks were thought to have been the result of attempts to reform the ghilman system of military slavery which was increasingly prevalent throughout the Islamic Middle East - the term "mamluk" already is derived from the Arabic word for "owned" or "property" - in other words, the property of a sultan or king (in Arabic, "malik"). Mamluks were used to bypass the need for a sultan to rely on the local nobility for military manpower, as many a caliph felt that local noblemen could not be trusted.