Alfonso X (1221—1284) reigned as king of Castile and León from 1252 until his death. Known to history as El Sabio, the Wise, or the Learned, his appreciation for science and the arts led him to sponsor a number of books on the history of Spain since its Roman settlement. Among them were the Cantigas de Santa Maria, a collection of over four hundred poems exalting his favorite patron saint, Mary, and chronicles of all the kings of Castile and León, Navarre, Aragón, and Portugal.

Alfonso X died before his own life could be written. His was a reign fraught with political intrigue and double crosses, almost constant war and equally constant diplomacy, royal largesse and economic instability — all of which led to open revolt and efforts by Alfonso's own son to depose the king. It would be another sixty-some years before King Alfonso XI would commission Fernán Sánchez de Valladolid to write Cronica de Alfonso X to memorialize his great-grandfather. As Alfonso XI's trusted counselor, ambassador, diplomat, and legist, Fernán was an understandable choice, but in the centuries since, his convoluted prose has proven extremely difficult extremely difficult for scholars.

Chronicle of Alfonso X is the first and only translation of the king's history. The original "clumsy Castilian" of Fernán Sánchez has now been transformed into literate and engaging English.