Legacy of Islam and Christianity

At the zenith of Muslim dominance in Spain, in the year 997, ruler Mohammed ibn Abu-Amir al-Mansur led a raiding party through the northern parts of the country, marching his troops as far as Santiago de Compostela. There, according to legend, his horse drank holy water from the church fountain while al-Mansur ordered the massive chapel bells hauled some 500 miles, on the backs of Christians, to the southern city of Córdoba, the center of Muslim power. The bells were melted down and made into lamps to illuminate the grand mosque, Córdoba's most magnificent and revered structure.

The distinctive striped arches inside the mezquita in Cordoba.

When Christian forces retook Córdoba in 1236, King Ferdinand iii didn't forget that bit of history. He ordered the lamps carried to Santiago—this time on the backs of Muslims—where they were melted down and refashioned into church bells.

The mosque at Córdoba, however, fared considerably better under the Catholic kings than had the ill-fated lamps. The Catholics completed the reconquista in 1492, yet rather than raze the mosque, as was the practice in other conquered cities, the new rulers simply consecrated the spot and constructed a Christian altar in the building's center. It is as quirky as it is distinctive. The mihrab, toward which Muslim worshipers direct their prayers, faces not southeast toward Mecca but directly south. (The reason for this seems to have been lost to the ages.) And even today, the Roman Catholic cathedral is still referred to by Christian worshipers as the mezquita, or mosque.

Contested. In fact, it was a holy and fiercely contested place long before the Muslims and Christians began their 800-year struggle for control of the Iberian Peninsula. The Romans constructed a pagan temple there to the two-faced Janus, the god of doors and gateways, beginning and endings. He would prove an apt deity for the site.

The Roman temple was later demolished to make way for the Visigothic Church of St. Vincent. On the ruins of that church, the Arab rulers began construction of the mosque. The Catholic kings altered much of the structure, bricking up the windows of the minaret, converting it to a bell tower, and carving saints around the ornate Moorish design patterns that decorate much of the complex's surface. The caliph's palace was replaced by one for the bishop. The builders were eager to show their new construction to Emperor Charles V, who told them frankly: "You have destroyed something unique to build something commonplace."

It is hardly commonplace, given both its enduring beauty and a history that continues to resonate. Al Qaeda leader Osama bin Laden has called for Arabs to retake Al Andalus, the ancient Muslim colony in southern Spain, of which Córdoba was the capital.

The identity of southern Spain has been a point of contention since the temple of Janus fell, straddling, as it does, the European and Islamic worlds. The period of Muslim hegemony in Spain is regarded as one of prosperity and scientific and cultural advancement—a mini-Enlightenment that came to a halt with the return of the Catholic kings and the Middle Ages. Córdoba was the most powerful and advanced city in the region, outshining even Baghdad and Damascus in terms of science and administration.

The mezquita, to befit such a city, was built to hold more than 5,500 worshipers and incorporated the latest technology of its day, including iron irrigation channels for the many orange trees in the courtyard. But as the last bastion of Muslim power, it thus finds itself at the center of a complicated history. The disposition of the mosque is occasionally evoked by Christian and Muslim clerics. Muslims recently sought permission to hold prayer services inside the mosque but were rebuffed by Catholic leaders.

Beyond Spain, it's now best known to tourists who flock to see the 850 delicate columns and red-and-white arcos de herradura, or horseshoe arches, that support the roof of a complex nearly the size of St. Peter's Basilica.