The aim of this paper is to analyze the traces of the first military constructions met by the Almoravids (the ones located in Sijilmasa) in the walls of Marrakech and Al-Andalus. In this way, the Saharan influence in the Almoravid military architecture has been documented. This influence has been still present during the first half of the 12th century (at least until 1126), when the Almoravid walls were built and repaired.