[6] Portugal started to occupy parts of coastal Morocco in 1415 with the Conquest of Ceuta, which was besieged unsuccessfully three years later by the Moroccans.

This restriction would only end with the dynastic union of the Portuguese and Spanish crowns under Philip II after the 1578 Battle of Alcácer Quibir, when Spain began to take direct action in Morocco, as in the occupation of Larache in 1610.

Of the six stand-alone fortresses, four only had a short duration: Graciosa (1489), São João da Mamora (1515), Castelo Real of Mogador (1506–10) and Aguz (1520–25).

[10] The Portuguese had to abandon most of their settlements between 1541 and 1550 (Safi and Azamor in 1541, Alcácer-Ceguer in 1549, and Arzila in 1550) following the offensives of the Saadi Sultan Mohammed ash-Sheikh, particularly the Fall of Agadir in 1541 and the Capture of Fez in 1549.

[10] The Battle of Alcácer Quibir in 1578 was a landslide loss, as the Portuguese King Sebastian was killed in the encounter and saw his army eliminated by Moroccan forces.