The first fort on the site was constructed by the Ottomans, Fort Santa Cruz is located 400 metres (1,300 ft) above sea level on on the Pic d’Aidour (Mount Murdjadjo) above Gulf of Oran.
The current structure was built by the Spanish between 1577/984 AH and 1604/1012 AH and housed several hundred soldiers and the residence of the Spanish general governor of Oran. It was restored in 1854-1860/1270-1276 AH.
SOURCES:
Abadie, Louis. "Le Fort Santa-Cruz." Oran Et Mers El Kebir: Vestiges Du Passé Espagnol. Nice, France: GANDINI JACQUES, 2002. 63-74.
"An Ottoman-Spanish Fort in Algeria - World Bulletin." World Bulletin.
February 7, 2014. Accessed October 27, 2014.
http://www.worldbulletin.net/news/128403/an-ottoman-spanish-fort-in-algeria.