|King Alfonso X The Wise at the Toledo school of translators|
The School went through two distinct periods separated by a transitional phase. The first was led by Archbishop Raymond of Toledo in the 12th century, who promoted the translation of philosophical and religious works, mainly from classical Arabic into Latin. Under King Alfonso X of Castile during the 13th century, the translators no longer worked with Latin as the final language, but translated into a revised version of Castilian. This resulted in establishing the foundations of the modern Spanish language.
Traditionally Toledo was a center of multilingual culture and had prior importance as a center of learning and translation, beginning in its era under Muslim rule. Numerous classical works of ancient philosophers and scientists that had been translated into Arabic during the Islamic Golden Age "back east" were well-known in al-Andalus (Islamic-era Spain) such as those from the Neoplatonism school, Aristotle, Hippocrates, Galen, Ptolemy, etc., as well as the works of ancient philosophers and scientists from Persia, India, and China. These enabled Arabic-speaking populations at the time (both in the east and in "the west" or North Africa and the Iberian peninsula) to learn about many ancient classical disciplines that were generally inaccessible to the Christian parts of western Europe, and Arabic-speaking scientists in the eastern Muslim lands such as Ibn Sina, al-Kindi, al-Razi, and others, had added significant works to that ancient body of thought.
Some of the Arabic literature was also translated into Latin, Hebrew, and Ladino, such as that of Jewish philosopher Moses Maimonides, Muslim sociologist-historian Ibn Khaldun, Carthage citizen Constantine the African, or the Persian Al-Khwarizmi.
Spain's multi-cultural richness beginning in the era of Umayyad dynasty rule in that land (711-1031) was one of the main reasons why European scholars were traveling to study there as early as the end of the 10th century. As the Arabic-speaking rulers who initially came in 711 intermingled and intermarried with local populations, the co-existence of Arabic, Hebrew, Latin, and the local Romance vernacular had seen the emergence of new pidgin vernaculars and bilingual song forms, as well as the creation of new bodies of literature in Arabic and Hebrew. The environment bred multi-lingualism. This era saw the development of a large community of Arabic-speaking Christians, known as (Mozarabs), who were available to work on translations. But translating efforts were not methodically organized until Toledo was reconquered by Christian forces in 1085. The new rulers inherited vast libraries containing some of the leading scientific and philosophical thought not only of the ancient world, but of the Islamic east, the cutting edge of scientific discourse of the era—and it was all largely in Arabic.
Another reason for Spain's importance at the time is that Christian leaders in many other parts of Europe considered many scientific and theological subjects studied by the ancients, and further advanced by the Arabic-speaking scientists and philosophers, to be heretical. The Condemnations of 1210–1277 at the medieval University of Paris, for example, were enacted to restrict the teachings of several theological works, among which were the physical treatises of Aristotle and the works of Averroes (the Latinized name of the Muslim philosopher-physician of al-Andalus, Ibn Rushd).
The translations of works on different sciences, such as astronomy, astrology, algebra, medicine, etc. acted as a magnet for numerous scholars from all over Europe who came to Toledo eager to learn first hand about the contents of all those books that had been out of reach to Europeans for many centuries. Thanks to this group of scholars and writers, the knowledge acquired from the Arab, Greek and Hebrew texts found its way into the heart of the universities in Europe. Although the works of Aristotle and Arab philosophers were banned at some European learning centers, such as the University of Paris in the early 1200s, the Toledo's translations were accepted, due to their physical and cosmological nature.