In the 13th century, there were many languages spoken in the Christian sections of what is now Spain, among them Castilian, Aragonese, Catalan, Basque, Galician, Aranese, Asturian and Leonese. But throughout the century, Castilian (what is also known today as Spanish) gained more and more prominence in the Kingdom of Castile as the language of culture and communication. One example of this is the El Cid. In the last years of the reign of Ferdinand III of Castile, Castilian began to be used for certain types of documents, but it was during the reign of Alfonso X that it became the official language. Henceforth all public documents were written in Castilian, likewise all translations were made into Castilian instead of Latin.
Furthermore, in the 13th century many universities were founded in León and in Castile, some, like those of the leonese Salamanca and Palencia were among the earliest universities in Europe. In 1492, under the Catholic Monarchs, the first edition of the Grammar of the Castilian Language by Antonio de Nebrija was published.