Please consider the spanish reconquest for it
starting in 711 with the muslim, north african invasion of visigothic hispania. Limited to the Iberian peninsula + maybe a bit of north africa. There were several christian kingdoms that arose and disappeared, warred mainly against the muslims but also among them. The muslim areas also had plenty of infighting and was very dinamic in their configuration.
There were several interesting characters, that often swapped sides, and there could be an interesting unit variation, i.e. visigothic/vasconic/frankish and arab/berber/other north african.
Some glorious battles took place during this period too, i.e Navas de Tolosa or the basques thrashing of Charlemagne's troops