Between the 10th and 15th centuries a number of figures linked to astronomy stood out in the different kingdoms of the Iberian peninsula. Among those active before the new millennium were Maslama al-Majriti and Lupitus of Barcelona (also known as Sunifred). They were not the only ones: Al-Zarqali (Arzaquel), Abu Muhammad Jabir ibn Aflah (Geber), Isaac ibn Sid (Rabbi Çag), to name only a few, also shone with their own light. Many were within the orbit of Toledo and its two schools of translators (12th and 13th century, the latter dominated by the figure of Alfonso X “The Wise”). The last example of Hispano-Muslim science was Al-Qalasadi in the 15th century, shortly before the conquest of the Kingdom of Granada in 1492. By then, powerful universities had arisen further north, both in Spain and other European countries, which had taken up the torch of Greco-Roman knowledge and begun a cultural revolution through Humanism and the Renaissance. In any event, in what context did all these individuals appear?
The swift Islamic expansion, which began in 622, reached the Iberian peninsula in 722. The conquest of the Visigoth kingdom was over in 726, always driven forward by the Umayyad caliphate, whose capital was Damascus. After the change of dynasty, its remaining members created the independent emirate of Cordoba, which would last from 756 to 929, and became a caliphate until 1031. Later it would be divided into numerous petty kingdoms or “taifas”, which would remain impotent in practice before the military thrust from the Christian kingdoms of the North or the invasions by the Almoravids (landing in 1086) and Almohads (from 1145), boosted by a greater religious zeal. However, the different courts flourished to an extraordinary extent at various times, above all culturally.
The intellectual splendor of the Caliphate of Cordoba
Cordoba under the caliphate was one of the major cities of the time, rivaling Constantinople, which was at the other end of the Mediterranean and becoming a major cultural focal point. The library of the caliph Al-Hakam II (915-976) would bring together hundreds of thousands of volumes, according to the chronicles. Unfortunately, after his death it was purged and dispersed. Many of its scientific texts were condemned to be destroyed in 979 by his chancellor Almanzor, the military leader who would become de facto ruler. As a result, three years after the death of the caliph and with the heir Hisham II being a minor, an irreplaceable collection was lost.
In any event, the period of the caliphate was the start of a great cultural flowering on the Iberian peninsula. Astronomy was inevitably an essential part of this, and in fact it is possible to identify the person responsible for starting astronomical activity in Al-Andalus: Maslama al-Majriti  or Majriti, who lived between the first half of the 10th century and the year 1007 or 1008. He was born in Madrid, a city created around a fortress constructed by the emir Muhammad I with the aim of protecting the borders of the Middle March against the attacks of the Christian kingdoms. Celebrated as one of the most brilliant personalities in the caliphate of Cordoba, Al-Majriti was dubbed the “Andalusian Euclid” and created an influential school that included astronomers and mathematicians such as Ibn al-Saffar, Abu al-Salt, Ibn al-Samh, Said Al-Andalusi, Ibn Barguth, al-Kirmani, Abu Muslim Ibn Khaldun, Abu Bakr ben Bashrun and Al-Turtushi (a well-known specialist in political theory), some of them direct students of the Madrid-born Al-Majriti.
Al-Majriti  improved the previous translations of Claudius Ptolemy (an influential Greco-Roman sage who lived in imperial Alexandria in the 2nd century, whose legacy was “Almagest”, a well-known astronomical treatise, and “Geography”, an influential text on this discipline), particularly his treaty “Planispherium” on the planisphere, probably with versions in Arabic, and drew up tables on the movements of the planets called “Sindhind“, calculations carried out by the illustrious al-Juarismi in the Baghdad of the caliphate of the Abasi dynasty 150 years earlier. He carried out this work together with his student al-Saffar, and it has reached us in the Latin translations of Petrus Alfonsi and his student Abelard of Bath. In the process of adapting the reference positions from the East to Al-Andalus, necessary for creating the astronomical tables, he estimated the size of the Mediterranean with a result that is notably smaller than that of Ptolemy although the new value would only be accepted in the world of Al-Andalus and Ptolemy would hold sway in this matter until the 16th century. Al-Majriti also introduced techniques of triangulation and cartography in his school and from there across Iberia. His observations on the stars, using the star Regulus as a reference, allowed him to determine that the succession of equinoxes, a phenomenon produced by the change in the orientation of the axis of the earth’s rotation in a cycle of nearly 26,000 years, had provoked a shift of more than 13 degrees with respect to the positions measured in the 2nd century by Ptolemy. As the start to a school, it can only be called “brilliant”.
David Barrado Navascués
European Space Astronomy Center (ESAC, Madrid)
 His full name was Abū al-Qāsim Maslama ibn Aḥmad al-Ḥāsib al-Faraḍī al-Majrīṭī
 Casulleras, J., “Majrīṭī: Abū al-Qāsim Maslama ibn Aḥmad al-Ḥāsib al-Faraḍī al-Majrīṭī”. In “The Biographical Encyclopedia of Astronomers”, Thomas Hockey et al. (eds.), Springer Reference. New York: Springer, 2007, pp. 727-728