Original sentence: In the 8th century, nearly all the Iberian peninsula, which had been under Visigothic rule, was quickly conquered (from 711), by Muslims (the Moors), who had crossed over from North Africa, as part of the conquests of the religiously inspired Umayyad empire
Edited sentence: In the 8th century, nearly all the Iberian peninsula, which had been under Visigothic rule, was quickly conquered (from 711), by Muslims (the Moors), who had crossed over from North Africa after crushing the Christian kingdoms there, as part of the conquests of the religiously inspired Umayyad empire