Alright, so the following is an (edited) idea for a TL:
Caliph Hasham II succeeded to the caliphate of Cordoba aged ten in 976; his minority allowed for his father's ambitious vizier, Al-Mansur (among others) to effectively rule from behind the throne. Indeed, for most of his life, Hasham was essentially a hostage, kept in a golden cage. It is arguable that many of the reasons for the collapse of the caliphate have their origin in these events, as Al-Mansur is also infamous for hiring thousands of Berber mercenaries, creating political tensions that would escalate into civil war and fragmentation by the early eleventh century (the Berbers were unhappy with rule by an arab minority that they outnumbered; Al-Mansur's ambitions also did not help things).
WI Caliph Al-Hakam II, Hasham's father, had managed to live longer, say until he was around seventy-two (he was known to be healthy)? This would push up Hasham's succession to around 987, by which time the boy would have been twenty-one. Let's also assume that during this time Al-Mansur finally slipped up and reached too far, and as a result was executed. This is not too outrageous, considering the caliph's other primary advisor (and ironically the vizier's own father in law), general Ghalib, was known to be the Al-Mansur's rival by the later years of Al-Hakam's reign, and could easily have participated in the vizier's downfall.
Assuming all of this, my idea is to have an Umayyed caliphate in Spain which surives for quite sometime. Understandably there would be many butterflies.
What are everyone's thoughts, opinions, ideas, etc.?