Seven centuries in Iberia: al-Andalus, the Christian kingdoms, Las Navas de Tolosa and the making of Spain and Portugal.
The Reconquista is a name given long afterwards to something that was never a single project: the seven-hundred-year process by which Christian kingdoms in northern Iberia expanded south at the expense of Muslim al-Andalus, ending with the fall of Granada in 1492.
The archive is careful with the word. For most of the period the frontier was not a religious front line but an ordinary political one, crossed constantly by mercenaries, exiles, tribute arrangements and alliances that ignored religion entirely. El Cid, the great hero of the Castilian tradition, spent years in the service of the Muslim ruler of Zaragoza. Christian kings allied with taifa emirs against other Christian kings, and vice versa, throughout.
What changed the character of it was the arrival of the Almoravids and then the Almohads from North Africa, which introduced a genuinely ideological element on both sides, and the papal grant of crusade status to Iberian campaigns. Las Navas de Tolosa in 1212 is the conventional turning point: after it, Almohad power in Iberia collapsed and the southern conquests followed quickly.
The other outcome is Portugal, which separated from León in the twelfth century and became a kingdom in its own right — a story the archive covers in its own detail.