The eldest son of Ferdinand III of…
1252 CE
The eldest son of Ferdinand III of Castile and Elisabeth of Hohenstaufen is already known as a scholar when, in 1252, he succeeds his father to become Alfonso X of Galicia, Castile and León.
He is immediately faced with a Muslim revolt, which he crushes.
Alfonso begins employing Jewish, Christian and Muslim scholars at his court, primarily for the purpose of translating books from Arabic into Old Spanish. (Most of these books survive in only one manuscript and were almost certainly created for the private use of Alfonso and his inner circle, which included Jewish and Christian courtiers.)
Work begins on the recording of the Alfonsine tables, astronomical tables based on calculations of al-Zarqali Alzarquel that divided the year into three hundred and sixty-five days, five hours, forty-nine minutes, sixteen seconds.
The Alfonsine tables are to be the most popular astronomical tables in Europe until late in the sixteenth century, when they will be replaced by Erasmus Reinhold's Prutenic Tables, based on Nicolaus Copernicus's De revolutionibus orbium coelestium.
Alfonso initiates the extensive use of the Castilian language, although his father, Fernando III, had begun to use it for some documents, instead of Latin, as the language used in courts, churches, and in books and official documents.