The city of Toledo was an important center of learning during the tenth and eleventh centuries, and when the Christians took over in 1085, the transfer of power was peaceful. As a result, even though the majority of the Muslim elite emigrated south, their culture was preserved, libraries were protected and the various communities of Jewish, Arab, Mozarabic, and Christian scholars were able to work together. This was especially important for the program of translation from Arabic to Latin (often via Hebrew or Romance) that followed. In the early Middle Ages, Spain was a multilingual society. Under Muslim rule, Arabic was the language of education and government, but Romance was spoken on the streets and in the fields, intermingled with various Berber dialects. Latin was the language of the Mozarabic Church, and of course Hebrew was ever-present in the large Jewish communities. When Toledo was reconquered by the Christians, Latin, the language of the Catholic Church, took on an increasingly important role, but the Mozarabs continued to use Arabic until well into the fourteenth century.
The European scholars who came to Toledo soon after the reconquest were staggered by the wealth of knowledge they found there. In the medieval period, Arabic book culture positively dwarfed that of Western Europe; the twelfth-century scholar Bernard of Chartres was proud of the twenty-four books he owned, but, in 1258, the city of Baghdad boasted thirty-six public libraries and over a hundred book merchants. The largest medieval library in Christian Europe, at the Abbey of Cluny, contained a few hundred books, while the royal library of Córdoba had 400,000. Even if we allow for exaggeration and the fact that the Arabs still mainly used scrolls, which could not contain as much text (several would be needed for one copy of a codex), and that paper was not produced in Western Europe until the fourteenth century, so it had to be imported, making books more expensive, the comparison is still shocking. Arab textual culture was not only much larger, it was also infinitely richer. The scale of Arab accomplishment in literature, history, geography, philosophy, and, of course, science left Latin scholars dazzled, giddy with awe. There was a lot of catching up to do.