This Lesson's logo is a Spanish caravelle

Developments in what is today Spain lagged behind those of Portugal, which had managed to expel the Moors from its territory two hundred years earlier than its eastern neighbor on the Peninsula. During the period of the Reconquista Spain was not a single nation, but rather a collection of small kingdoms, principalities and other regions under the control of local knights who had risen to power during the long struggle against the Moors. Two of the principal kingdoms were those of Castille and Aragon, which by the 15th century controlled most of the central and eastern part of the Peninsula. In the year 1469 Isabel of Castille and Ferdinand of Aragon married, setting the stage for national unification of Spain when they inherited their respective thrones a few years later, and were proclaimed "the Catholic Monarchs" by the Pope. The sovereigns ruled for a momentous quarter century that saw the final defeat of the Moors, Columbus' voyages, the expulsion (or forced conversion) of the Arabs and the Jews, and the rise of the Castillian language (Spanish) as the dominant tongue of the emerging nation of Spain.

The year 1492 was decisive. On the 2nd of January the last Arab stronghold of Granada fell. Any remaining Moors had to either accept conversion to Christianity or leave. The same held for the Jews, and the Inquisition was created to guarantee the purity of the Roman Catholic religion in Spain. That same year Antonio de Nebrija published the first grammar of the Castillian language; when the book was presented to Queen Isabel, it was noted that "language is the perfect instrument of empire". And in August of 1492 an obscure navigator named Columbus, in the service of the Catholic Monarchs, set out to find India by heading west across the Atlantic instead of east, as the Portuguese had already done.