Muhammad ibn Muhammad al-Idrisi

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Muhammad ibn Muhammad al-Idrisi

The Arab geographer Muhammad ibn Muhammad al-Idrisi (1100-1165) wrote the Book of Roger, a world geography, for King Roger II of Sicily. His work, marking the end of the classical age of Arab geography, sums up much of its achievement.

Al-Idrisi was born in Ceuta in Morocco, a descendant of the sharifian Hammudid dynasty, which had ruled over Málaga until 1057 and over Ceuta and Tangier until 1084. He studied at Cordova, the center of scholarship in Moslem Spain. In his youth he traveled widely, visiting Asia Minor, North Africa, Spain, France, and probably the English coast. At the invitation of Roger II, Norman king of Sicily, he went, not later than 1144, to live at the latter's court in Palermo. Roger's motives in inviting him may have been partly political. Al-Idrisi, as a descendant of a dynasty ruling in Moslem Spain and North Africa, and having an intimate knowledge of these regions, must have seemed a useful tool in Roger's designs on establishing his hegemony over the western Mediterranean.

Roger also had, however, a keen theoretical interest in geography. Since 1139 he had sponsored an ambitious project for a world geography to be based on the Greek, Latin, and Arabic geographical literature as well as on contemporary reports and research. He appointed a commission to gather and sift the material. Al-Idrisi soon became its leading member and in this function developed into one of the great Arab geographers.

Book of Roger

At the order of the King, al-Idrisi produced a silver celestial sphere and an enormous map of the world in disk form cast on a silver base. As a commentary to it, he wrote his large geography of the world. It was completed in January 1154 and became known as the Book of Roger in recognition of the King's important role in sponsoring it.

In this work al-Idrisi divided the known world, in accordance with the Greek tradition, into seven climes and described each clime in detail moving from west to east. A world map and 70 sectional maps accompany the description. His conception of the world as reflected in the maps is more influenced by the Ptolemaic than the Arab tradition. Al-Idrisi used the geography of Ptolemy and many works of the Arab geographers as sources, though some important ones escaped him.

Al-Idrisi also relied on reports of contemporary travelers and, for the regions he had visited, on his own observations. Quite original and generally precise is his description of the countries of Europe, for which he had to rely almost exclusively on contemporary reports. Although an abridged version of the Book of Roger was published in Rome in 1592 and a Latin translation of it in 1619, the full text has never been edited. A complete edition was under preparation in Italy in the early 1970s.

After the death of Roger in 1154, al-Idrisi produced an enlarged version of his geography for Roger's son and successor, William I. This work is lost. Al-Idrisi left Sicily, perhaps as a result of the anti-Moslem riots in Palermo in 1161. Later he composed a shorter compendium of world geography which is extant in manuscript. Al-Idrisi also wrote a pharmacological treatise and some poetry. According to a conjecture on the basis of a poor source, he died in Ceuta in 1165.