In 955, Almería gained the title of medina ('city') by the Caliph of Cordoba, Abd ar-Rahman III: construction of the defensive citadel, located in the upper sector of the city, began in this period. The alcazaba, provided not only with walls and towers but also with squares, houses and a mosque, was to be also the seat of the local government, commanding the city and the sea nearby.
The complex was enlarged under caliph Al-Mansur and, later, under Al-Jairan, first king of the independent taifa of Almería (1012–1028).
The first line of walls is a wide enclosure corresponding to the first Muslim military camp, used as shelter for the population in case of siege. For this task it was provided with large cisterns.
The first enclosure is separated by the second one by the so-called Muro de la Vela ('Wall of the Sail'), taking its name from a bell that warned the population in case of events such as the arrival of a ship in the port, danger, fires etc. This wall was built by King Charles III of Spain.
In the second enclosure was the residence for the governors, their soldiers and their servants. It included also the mosque, baths, tanks, tents etc.
The third enclosure, the most external, is also the most modern in the complex. After the Christian conquest of Almería, the Catholic monarchs Isabella I of Castile and Ferdinand II of Aragon had a castle built in the most elevated sector of the town, more apt to resist the new gunpowder artillery.
References:Saint-Georges de Boscherville Abbey is a former Benedictine abbey. It was founded in about 1113 by Guillaume de Tancarville on the site of an earlier establishment of secular canons and settled by monks from the Abbey of Saint-Evroul. The abbey church made of Caumont stone was erected from 1113 to 1140. The Norman builders aimed to have very well-lit naves and they did this by means of tall, large windows, initially made possible by a wooden ceiling, which prevented uplift, although this was replaced by a Gothic vault in the 13th century. The chapter room was built after the abbey church and dates from the last quarter of the 12th century.
The arrival of the Maurist monks in 1659, after the disasters of the Wars of Religion, helped to get the abbey back on a firmer spiritual, architectural and economic footing. They erected a large monastic building one wing of which fitted tightly around the chapter house (which was otherwise left as it was).