The great mosque of Córdoba was begun by the Muslim caliphs in the eighth century, its forest of pillars and red-and-white striped arches meant to convey a powerful sense of the infinite. With the Christian reconquest of Spain in the 13th century, it was consecrated as a cathedral.

Today, signs throughout this whitewashed Andalusian city refer to the monument, a Unesco World Heritage site, as the "mosque-cathedral" of Córdoba. But that terminology is now in question. Last month, the bishop of Córdoba began a provocative appeal for the city to stop referring to the monument as a mosque so as not to "confuse" visitors.

For now, the matter is largely semantic because the mayor says the city will not change its signs. But the debate goes far beyond signs. It is the latest chapter in the rich history of the most emblematic monument in Christian-Muslim relations in Europe — and a tussle over the legacy of "Al Andalus," when part of Spain, under the Muslim caliphs, was a place of complex coexistence among Muslims, Christians and Jews. 

The debate takes on greater weight ahead of Pope Benedict XVI's planned visit this weekend to Spain, which he has identified as an important battlefield in his struggle to shore up Christian belief in an increasingly secular — and implicitly Muslim — Europe.

The polemic in Córdoba began in mid-October, when Bishop Demetrio Fernández published an opinion article in ABC, a Spanish center-right daily newspaper.

"There's no problem saying that the Muslim caliphs built this temple to God," the bishop wrote. "But it is completely inappropriate to call it a mosque today because it has not been one for centuries, and to call it a mosque confuses visitors."

"In the same way, it would be inappropriate to call the current mosque of Damascus the Basilica of St. John or to expect that it could be both a place of Muslim and Christian worship," Bishop Fernández added, referring to the Syrian site where an Umayyad mosque was built in the eighth century above a fourth-century church said to contain the remains of John the Baptist.

The Córdoba monument — one of the true architectural wonders of the world, with its rows of pillars that both disorient and overpower — drew 1.1 million visitors in 2009, most of them tourists, not worshipers. But diocesan officials are upset that some Muslims have tried to pray there, even though it is a consecrated cathedral.

"Every time some Islamic fundamentalist, in a video on Al Jazeera or other channels, calls for the re-conquest of Al Andalus, the old Muslim dominion, people show up here calling for the use of the cathedral as a place of Islamic worship," said the Rev. Manuel Montilla Caballero, who oversees the diocese's nighttime tours of the monument, which use dramatic lighting to showcase the splendid architecture.

Today, the legacy of Al Andalus is highly contested. While Osama bin Laden and other radicals have called repeatedly for the return of Al Andalus to Muslim hands — that is, for the Islamic reconquest of Spain and implicitly Europe — others look to Al Andalus as an almost utopian era of peaceful coexistence among Christians, Muslims and Jews.

The city also has a rich Jewish history. Maimonides, the 12th-century Jewish polymath philosopher, was born in Córdoba, in a modest white house in the Judería, now a tourist area where the local Jewish population lived before Ferdinand and Isabella expelled the Jews from the Iberian Peninsula in 1492.

In the following century, when Spain's Catholic rulers took to destroying Muslim and Jewish places of worship, the Hapsburg emperor Charles V is said to have been so captivated by the beauty of the Córdoba monument that he ordered its preservation.

"The Córdoba monument is a lesson in universalism, in how cultures and religions can meet and co-exist," said Isabel Romero, the spokeswoman for Córdoba's local Islamic association. Much to the diocese's displeasure, the group wants the diocese to create a space in the cathedral for Muslim worship. "It would be an exemplary gesture," Ms. Romero said.

In another complex twist, indicative of the historical ironies at work in today's Spain, Ms. Romero is a Catholic convert to Islam — as are 300,000 out of Spain's 2.2 million Muslims.

This week, a judge in Córdoba charged eight Austrian Muslims with disturbing the peace when they entered the monument in small groups on Good Friday this year, began to pray loudly and scuffled with security guards and local police officers who tried to stop them.

Meanwhile, a group called the Association of Muslims of Córdoba, which represents others among the 2,500 Muslims in this city of more than 300,000 people, says it has no intention of seeking the right for its members to pray in the mosque-cathedral.

"No, no, no," said Kamel Mekhelef, the secretary of the association, whose members pray in a mosque in Córdoba built in the 1940s by North African soldiers who fought for Franco. "To ask for shared worship is to fan the flames, to force the question and raise tensions," Mr. Mekhelef added.

But he said that he and his group were vehemently opposed to the bishop's suggestion of removing the word "mosque" from local signs.

"It's a tendency that I feel across Spain, a certain inclination to want to cancel anything related to Islamic Spanish history," he said.

Local officials say they have no intention of changing the signs. "The bishop's statement creates an unnecessary and useless polemic," said the mayor of Córdoba, Andrés Ocaña, from the United Left party. "It has no support among people, and obviously not among politicians, not even from the Popular Party," he added, referring to the center-right opposition.

A spokesman for the diocese, Juan José Jiménez Güeto, said the bishop declined to elaborate beyond his published remarks.

On a recent afternoon, visitors to the monument, standing beneath the rows of orange trees and clever irrigation canals in its courtyard, appeared split. "It's a cathedral and should be called a cathedral," said Daniel Ramírez, who was visiting from Seville. "It's not a question of terms; it's a question of our culture."

His friend Celestino González from Málaga disagreed. "It's a mosque," Mr. González said, pointing to the Islamic architecture. "I'm not practicing, and I don't see any problem in combining the two names. For me it's the same thing."

As Conchi Bello stood in the doorway to her house nearby, she said the debate was purely academic. "For us, for everyone in Córdoba, it's normal to give tourists directions to the mosque," Ms. Bello said. "We're not offended. On the contrary, it's a nice example of the history of our land."