Before this event, the Almohads had already gained control over a significant portion of Almoravid territories in North Africa and al-Andalus.
The Almohad movement, initiated by Ibn Tumart, sought to overthrow the ruling Almoravid dynasty.
[1] He reached his native land of Tlemcen in 1142/1143 where he recruited members of his tribe, the Kumiya, and other associated groups who were then incorporated into the Almohad army.
A jew from Sijilmasa named Solomon reported that during Abd al-Mu’mins conquest of Fez 100,000 Jews and Muslims were killed and in Marrakesh 120,000, although this is not to be taken it corresponds with Arabic sources that mention how the male population was put to the sword while the female population was sold into slavery.
[3] In the same year of the capture of Marrakesh, Abd al-Mu’min invaded Al-Andalus and between 1147/1148 gained possession of the southwestern quadrant of the Iberian peninsula.