Muslims across Spain are lobbying the Roman Catholic church in the southern city of Córdoba to make a symbolic gesture of reconciliation between faiths by allowing them to pray in the city's cathedral.
Córdoba's renaissance cathedral sits in the centre of an ancient mosque complex, and local Muslims want to be allowed to pray there again. They have appealed to the Vatican to intercede on their behalf.
Zakarias Maza, the director of the Taqwa mosque in neighbouring Granada, said yesterday: "We hope the Vatican will give a signal that it has a vision of openness and dialogue.
"It would be good if there were a gesture of tolerance on their part.
"Córdoba has been a symbol of the union of three cultures for centuries. Even now, Jews and Muslims live together with Christians in the neighbourhood around the mosque."
But he added: "The church council doesn't seem to be open to dialogue."
The Muslim community in the south of Spain is growing as a result of immigration from north Africa, and due to Spaniards converting. Córdoba now has some 500 Muslims, too manyfor the city's existing mosque.
There was widespread rejoicing among Muslims last year when a new and prominent mosque was opened in Granada after many years of negotiations, but church leaders in Córdoba appear reluctant to acknowledge the way Spanish society is evolving.
A spokesman for the local bishop told El Mundo that the proposal faced a lot of obstacles and it would be many years before it came to anything.
The proposals have also provoked anger in some parts of Spain's Catholic community.
"Will Christians be able to pray in the mosques of Morocco, Saudi Arabia, Iran or Kuwait?" demanded one contributor to a Catholic website. "Muslims should practise what they preach!"
The Muslim community is going out of its way to portray the proposals as a union, and not a clash of faiths. "In no way is this request about reclaiming our rights - far less any kind of reconquest," Isabel Romero, a member of the Islamic Council of Spain, told a local newspaper.
"Instead, we want to give our support to the universal character of this building."
Nowadays, Córdoba is a small provincial capital in one of the poorer regions in the Spanish interior, but 1,000 years ago it was one of the great cities of the world.
As the capital of Moorish Spain, Córdoba became one of Islam's holiest places, and a centre of Islamic art and scholarship to rival Baghdad.
The original mosque was built in the eighth century, following the conquest.
It was expanded by successive generations of rulers until the city was taken by the Christians again in the 13th century.
With its hundreds of marble columns and distinctive red-and-white brickwork, the mosque is considered one of Moorish Spain's greatest legacies, despite the 16th-century addition of the cathedral in its centre.
It stands at the heart of a Unesco world heritage site.
The addition of the cathedral was only the most recent change of use for a site that has seen the ebb and flow of the world's great religions.
The Visigoths had their own cathedral on the site before they were defeated by the Moors. Before that, a temple to the Roman god Janus had stood there.
For Muslims, the most important part of the mosque is the mihrab, the recess in the south-eastern wall which indicates the direction of Mecca for prayer.
In the Córdoba mosque, the mihrab is outside the cathedral itself, so in theory it would be possible for Muslims to pray without affecting ceremonies in the cathedral.
The Islamic Council has lodged a formal request with the Vatican for Muslims to be allowed to pray in the mosque. "The request was very well received," Mansur Escudero, secretary of the Islamic council, told El Mundo.
The plan also has support from local politicians. Antonio Hurtado, a spokesman for the local Socialists, told El Mundo: "We hope to see Córdoba become a place for the meeting of faiths."
The city's United Left (IU) mayor, Rosa Aguilar, is also believed to be in favour of the move, although she has said that now is not the time for the council to debate the issue.
"There has been a series of meetings between the IU and the Islamic Council to open up a dialogue between religions," her deputy, Andrès Ocaòa, told Europa Press. "In today's world, we have to make every effort to maximise our knowledge of different cultures to help us live together better."