Tabula Rogeriana

Around 1138, the Norman King of Sicily, Roger II, invited Al-Idrisi, a Muslim geographer, to his court in Palermo, in search of help pursuing his political agenda. Sicily's vibrant multicultural environment led al-Idrisi to accept King Roger's invitation to his court. During the meeting, Al-Idrisi briefed Roger II on his familiarity and personal experiences traveling around North Africa and Western Europe, which prompted Roger II to commission an atlas from Al-Idrisi. To produce the work, Al-Idrisi started gathering information for the maps by interviewing experienced travelers on their knowledge of the world, keeping "only that part... on which there was complete agreement and seemed credible, excluding what was contradictory." The primary influence for Al-Idrisi's cartography can be found in Arabic translations of Ptolemy's Geography, which laid out many of the principles he utilized in his work. Al-Idrisi also derived map-making methods from the Balkhi school of Geography, a school which was founded during the 10th century in Baghdad under the Abbasid Caliphate. It was from this school that he drew the scientifically rigorous and anthropologically detailed information that he incorporated into the atlas' creation. He also used some instruments King Roger II created to help calculate latitudes and longitudes. This research process ultimately took some 15 years. In 1154, just a few weeks before the king died, Al-Idrisi completed his atlas, producing a book with 70 sectional maps and a silver disc engraved with the composite world map they formed. This would become known as the , as well as the Book of Roger. This disc was made in accordance with Al-Idrisi's calculations of the circumference of the earth, and would lead to the later creation of a silver globe with the same map engraved on it. ==Description==

The book, written in Arabic, is divided into seven "climatic zones" (in keeping with the established Ptolemaic system), each of which is subdivided into ten sections. Each section is given its two-page spread map, for a total of 70 maps. The maps are oriented with North at the bottom, South at the top, with Mecca in the middle. Each map was organized according to a coordinate system that, while inaccurate by modern standards, nonetheless ensured a level of rigor and consistency in scale from map to map. Al-Idrisi added pages of commentary following each map he produced. The text incorporates descriptions of the physical, cultural, political, and socioeconomic conditions of each region. This information was largely accurate, with inconsistencies being attributable to flawed accounts from the travelers interviewed. A total of 10 copies remain in various conditions, 5 of which are complete manuscripts. == Significance ==

This set of maps was profoundly influential for centuries to come. Many contemporary scholars hailed it as the greatest work of geography of the period. Moreover, the atlas influenced later geographical works with its techniques, inspiring maps with similar levels of precision. Additionally, Al-Idrisi's maps represented a shift in the philosophy of cartography. While the coordinates used were inaccurate by modern standards, they nonetheless illustrate that map-making was principally a scientific endeavor. Unlike previous cartographers, al-Idrisi aimed to be as accurate as possible and to provide as much reliable information about the various regions of the world, especially those contained in Roger II's realm. This contrasts heavily with prior Christian maps, which were solely based on the writings of the Bible. Islamic cartographers, while generally more accurate than their Christian counterparts, were still liable to use abstraction in their mapmaking. This made al-Idrisi's map one of a kind in its scope and ambitions, applying the techniques of the Balkhi School of Geography to an unprecedented scale and including detailed descriptions of all regions that it portrayed. In the 19th century, the manuscript experienced renewed interest and popularity with the rise of orientalism and interest in the East. Orientalists widely reprinted the book. In 1799, in Madrid, Jose Antonio Conde reprinted the section on Andalusia in its original Arabic with a Spanish translation. In 1828, Rosen Muller reprinted the section on Greater Syria and Palestine in Leipzig. In 1864, Reinhart Dozy reprinted the section containing information about Morocco, Sudan, Egypt, and Andalusia in Leon. These maps were used in a variety of activities, ranging from display to being taught and studied. The most complete manuscript, which includes the world map and all seventy sectional maps, is kept in Istanbul. == See also ==