The Cathedral-Mosque of Córdoba was originally a polytheistic temple, which was replaced with a Christian church during the Visigothic period of rule in Iberia. Following Muslim conquests of the region, the site was split between Muslims and Christians. When the heir to the Umayyad Caliphate fled a coup in 750 CE in Syria, he managed to establish a rival caliphate on the Iberian peninsula. As the first Iberian Caliph, Abd al-Rahman I purchased the Christian portion of the space, and effectively rebuilt most of the mosque. Large sections of the site, now used as a cathedral, date to that period.
Often Iberian Umayyad art and architecture recalls the origins of the caliphate as exiled leaders of the Muslim world, originally from modern Syria. Ablaq (alternating coloring in archways) is frequently used, undoubtedly in part because it is strongly associated with that region, where it appears to have originated as an architectural form. The pillared halls the cathedral-mosque recall this especially well, with multiple stacked layers of supportive arches - all with red and white ablaq.
(Photo credits - Ian Pitchford above, Melanie Michailidis below)