When Umayyad Caliph al-Hakam II decided to expand the Grand Mosque of Cordoba, in 965, he faced a problem: mosaic-making knowhow had disappeared from this part of southwestern Europe half a millennium before, when the Romans were driven out of Hispania. Without it, al-Hakam II’s prospects of emulating his ancestors and recreating the kind of splendid, Byzantine-style mosaics attained in Damascus’ Umayyad Mosque were slim. So he sent a message East to Constantinople and Byzantine Emperor Nicephorus II, asking for a little capacity-building support in order that he might create, in his dynasty’s Andalusian exile, a reminder of its Syrian homeland.