Spanish Reconquista: the forces of the Kingdom of Castile initiate the ultimately futile Siege of Algeciras against the Emirate of Granada.

The Reconquista or the fall of al-Andalus was a series of military and cultural campaigns that European Christian kingdoms waged against Muslim-ruled al-Andalus, culminating in the reign of the Catholic Monarchs of Spain.

The Kingdom of Castile was a polity in the Iberian Peninsula during the Middle Ages. It traces its origins to the 9th-century County of Castile, as an eastern frontier lordship of the Kingdom of León. During the 10th century, the Castilian counts increased their autonomy, but it was not until 1065 that it was separated from the Kingdom of León and became a kingdom in its own right. Between 1072 and 1157, it was again united with León, and after 1230, the union became permanent.

The siege of Algeciras was the first of many sieges of the city by Christian forces in the lengthy period of the Spanish Reconquista. The siege, ordered by King Alfonso X of Castile also known as "el Sabio", was a fruitless military campaign initiated by the Kingdom of Castile with the objective of removing the Benimerins from Algeciras. The siege on Algeciras, then known to the Muslims as Al-Jazira Al-Khadra, was strategically important because Algeciras had been at the time the main fortress and landing place for African reinforcement troops in the Iberian Peninsula. Castile, which had a powerful armada of ships anchored in the Bay of Gibraltar to blockade such reinforcement, had a few days previously to the siege, seen that fleet obliterated by the Muslim admiral, Abu Yusuf Yaqub at the Naval Battle of Algeciras.

The Emirate of Granada, also known as the Nasrid Kingdom of Granada, was an Islamic polity in the southern Iberian Peninsula during the Late Middle Ages, ruled by the Nasrid dynasty. It was the last independent Muslim state in Western Europe.