or translated from Islamic sources. This huge amount of writing based out of Toledo, in fields previously reserved for Latin, had a standardizing effect on written Romance in the area. It also led to a massive expansion of Castilian's vocabulary, mainly achieved through borrowing, but also through derivation, especially through the use of suffixes. The syntax of written Spanish also became a lot more elaborate, with a greater number of subordinate clauses, and fewer clauses connected with 'and'. Additionally, the orthography, which had been quite chaotic at the beginning of Alfonso X's reign in the mid-13th century, became systematized, although it was not entirely free of variation. Alfonso X's promotion of writing in Castilian was likely intended in part to have a unifying effect on his kingdom. Each of the three more well-established written languages, Latin, Hebrew and Arabic, was associated with a particular religious community, while Castilian or a closely related dialect was spoken by nearly everyone. Renaissance and Golden Age The first grammar of Castilian, and the first explicit codification of any modern European language, was published in 1492 by Antonio de Nebrija. Further commentary on the language was offered by Juan de Valdés in 1535. At around the same time, early printers also played a strong standardizing role. Nebrija notably described the Spanish language he sought to codify as a companion of empire in his address to Queen Isabella, at the time referring to Spain's possessions in Europe and not to Spain's soon-to-be-conquered possessions in the Americas. After the settling of the Royal Court at Madrid, and subsequent dialect mixing and the establishment of new varieties spoken in Madrid, standard written Spanish became primarily based on the speech of Madrid, even though its origin is sometimes popularly assigned to other cities, such as Valladolid. The Early Modern Spanish of the 16th and 17th centuries is sometimes called classical or Golden Age Spanish, referring to the literary accomplishments of that period. Spanish orthography was still far from consistent during this time. The gap between the largely unchanged system developed under Alfonso X and spoken Spanish expanded due to changes such as the evolution of sibilants and the loss of , which occurred during this time, and betacism, or the merger of the phonemes and , which had become complete in northern Spain by the fifteenth century. One notable case of grammatical variation in Spanish has to do with