Abd-er-Rahman III (912-961) was by far the greatest ruler in the history of Moslem Spain. His first problem was the establishment of the central power. Within a few years he had reduced not only the Renegado states of Toledo, Aragon, Extremadura, and Bobastro but also the aristocratic Arabs and the Berber chiefs in various parts of Spain. He then changed his title from that of emir to caliph, thus signifying his intention of maintaining a robust absolute monarchy. He also drove back the Christian kings in the north, after which he proceeded to cultivate friendly relations with them. Even the Moslem province in northwestern Africa fell under his sway. In administrative matters as well Abd-er-Rahman III proved his ability. Not only did he create a great army but he also increased the strength of the navy (which the emirs before him had already founded) until it became the most powerful fleet in the Mediterranean Sea. Spain was recognized as the greatest state in Europe, and in western Europe it was also the centre of the highest culture. Through the caliph’s measures agriculture, industry, and commerce, and education, literature, and the fine arts developed to a high point, and Cordova became a city of half a million inhabitants. [Sidenote: Almansor.] Hakem II (961-976) continued his father’s policy in all respects, but was able to devote even more attention to intellectual activities. In military affairs the next reign, that of Hisham II (976-1013), was particularly brilliant, but it was not the caliph who directed affairs. In the time of Hakem II a certain Mahomet-ben-Abdallah-abu-Amir had attracted the attention and won the heart of the caliph’s favorite wife. Through her aid he became the chief minister of Hisham II, who was a minor at the time of his succession. Hisham was soon put aside by Mahomet, who sequestered the caliph in the palace, and ruled in the name of the virtually deposed monarch. Mahomet was principally famous for his victories, on account of which he was called Almansor, meaning “the aided of God,” or “the victorious by divine favor.” He reorganized the army, making it a machine which was not only efficient in a military way but also personally devoted to him. Then in repeated campaigns he defeated the Christian kings of the northwest and northeast, reducing the greater part of their territories to his authority, and making himself arbiter in the kingdoms which were allowed to exist. [Sidenote: Downfall of the caliphate.]