Officially known as the Cathedral of Our Lady of the Assumption, the Mosque Cathedral of Cordoba in Spain is a stunning monument and one of the oldest structures from the time of Al-Andalus that included most of Spain, Portugal and a section of Southern France, ruled by the Muslims in the late 8th century.

It is believed that the site was originally occupied by a Roman temple dedicated to Janus, which was later converted into a church, possibly the Catholic Basilica of Vincent of Lerins, by the invading Visigoths who seized Cordoba in 572, during the rule of the Visigothic Kingdom in the Iberian Peninsula, located in the southwest corner of Europe.

However, when the Umayyads were overthrown in Damascus by the Abbasid Revolution in 748-750, Prince Abd al-Rahman I fled from Damascus to southern Spain and soon established control over almost all of the Iberian Peninsula. He intended to recreate the grandeur of Damascus in his new capital, Cordoba and to erect a mosque which would rival in magnificence those of Baghdad, Jerusalem, and Damascus, and approach in sanctity the fame of Mecca. As he decided to raise his great mosque above the Christian church dedicated to Saint Vincent, he allowed the Christians to rebuild their ruined churches and purchased half of the church of St Vincent. Thus, the Visigoth structure was divided into two halves and used as a place of worship by both Muslims and Christians.

But the religious pluralism in Córdoba ended in 784 when Emir Abd al-Rahman ordered to destroy the church, and the construction of his dreamed mosque began. The huge process of construction continued for more than two centuries by the descendants of Abd al-Rahman, as it underwent numerous subsequent changes. However, when the building was completed in 987 with the addition of the outer nave and the courtyard, the unique mosque of Cordoba proved to be the largest in the Islamic kingdom, save only for that of Kaaba in Arabia.

It is said that the Mezquita or the Mosque-Cathedral of Cordoba was planned by a famous Syrian architect and the ground plan of the building is in the form of a vast rectangle measuring 590 by 425 feet, which is little less than St. Peter’s Basilica in Rome.

The courtyard leads to a large hypostyle prayer hall, whose roof is supported by a forest of pillars. Those tall 856 columns of jasper, coloured marble, porphyry and granite were made from the pieces of the destroyed Roman temple that had occupied the site previously, along with other Roman buildings. The iconic and somewhat hypnotising double-arch feature was an architectural innovation, since single-arch columns of about seven or eight feet high would have been too low for the immense roof. The famous alternating red and white voussoirs, a wedge-shaped element used in building an arch, resemble those of the Aachen Cathedral in Germany.

(Ref - Aachen Cathedral Germany)

The most amazing part of the prayer hall is the famous horseshoe arched mihrab or prayer niche. The horseshoe-style arches were common in the architecture of the Visigoths and were known in the Iberian Peninsula since the Late Antiquity. The richly gilded mihrab or the prayer niche in the Great Mosque of Cordoba is framed by an exquisitely decorated arch. It is a small octagonal recess roofed with a single block of white marble, carved in the form of a shell and has walls inlaid with Byzantine-style mosaics and gold. The dazzling dome above the mihrab is built of crisscrossing ribs, creating pointed arches, covered with gold mosaic in a radial pattern. With geometric and flowing designs of plants, the mihrab is undoubtedly a masterpiece of architectural art.

The Mosque-Cathedral of Cordoba was built in four stages, with each ruler and his elite contributing to it. A four-faced minaret adorned with tracery and containing fourteen windows with arches upon jasper columns, along with two separate staircases for ascent and descent was built by Abd al-Rahman II. Around one hundred and fifty years after the construction of the mosque, a staircase to the roof was added, along with a southward extension of the mosque. A bridge, linking the prayer hall with the Caliph's palace was also built on a later date. 

Córdoba was recaptured by the Christians in 1236, but the Great mosque was never demolished. However, due to the alteration and additions by the Christian monarchs, it became a typical hybrid structure. Finally, it completely lost its Moorish character in the16th century with the erection of a central high altar and cruciform choir, along with the great Renaissance nave right in the middle of the Mezquita, by Charles V. Subsequently, numerous chapels were also created, along the sides of the vast quadrangle, and a 300 feet tall bell tower took the place of the old minaret.

The Mosque-Cathedral of Cordoba, enlisted in the UNESCO World Heritage Site since 1984, is one of the most astounding and significant buildings in the world.