The enigmatic orientation of the Great Mosque of Córdoba

The Great Mosque at Córdoba does not face Mecca as we moderns think it should. This is also true of many other medieval mosques. However, now that we have some control over the medieval textual sources relating to the Kaʿba and to the qibla, we can see that in the first two centuries of Islam, and occasionally also long thereafter, astronomical horizon phenomena were used to face the Kaʿba, itself astronomically aligned. From the 9th century onwards, mainly directions based on geographical data and mathematical procedures were used to align mosques towards Mecca. Nevertheless some of the earliest mosques, as in Jerusalem and Damascus, were aligned with pre-Islamic religious edifices or complexes. In the case of the Great Mosque of Córdoba, it was a suburban Roman street-plan, revealed by excavations only some 20 years ago, which defined the qibla-axis of the Mosque, and this happened to be one of the several qibla-directions favoured in al-Andalus. So in medieval terms the Mosque could indeed have been thought to be facing the Kaʿba.