The Alcazaba, a fortress, is the oldest part of the Alhambra, as is the case of the Vermilion Towers (Torres Bermejas). It is thought that before it was built and before the Muslims arrived to Granada, there were already several constructions in the same area. The first historical reference to the existence of the Alcazaba dates from the 9th century and it is believed that it was then built by Sawwar ben Hamdun during the fights between Muslims and muwalladins [Christians who converted to the Islam and lived among the Muslims].
The current complex was built by Mohammed I, who constructed the ramparts around the previous castle, defences and three new towers: The Broken Tower (Torre Quebrada), the Keep (Torre del Homenaje) and the Watch Tower (Torre de la Vela). As a consequence, the Alcazaba became a real fortress, where the king established the royal residence. His son Mohammed II also had his residence in the Alcazaba, until the palaces were finished. From then on, the Alcazaba was only used as a fortress for military purposes.
When the Christians took the city, they carried out many works to repair the Alcazaba. At different moments of its history, during long periods of time, it was used as a State prison, even during the French occupation.
Like the Alhambra, the Alcazaba was abandoned and not cared for during a long time and it was not until the late 19th century and beginning of the 20th century that the restoration, exploration and plumbing works were started.