When Saudi King Abdullah arrives in Rome on Tuesday he may wish to take a break from his schedule, including a historic meeting with Pope Benedict XVI in the Vatican, for a quiet moment of prayer at the city's central mosque, Europe's largest Muslim house of worship.
In the highly unlikely event of Benedict visiting Saudi Arabia, there the pontiff would not find a single church to pray in.
The kingdom prohibits all public religious display that are not Islamic and routinely refuses clerics from other faiths entry into the country.
Rome's Central Mosque, reportedly built for more than 50 million dollars largely donated by Saudi Arabia's former king Fahd, stands on a hilltop overlooking a city which is the centre of the Roman Catholic world.
The mosque was inaugurated in 1995 in a ceremony attended by representatives of the Catholic, Jewish and Buddhist faiths.
"Reciprocity is what we hope for, precisely because we permit the Saudi Arabians to have a place of worship here," Cardinal Francesco Colasuonno, the then Papal Nuncio or envoy to Italy who attended the inauguration, was quoted as saying at the time.
"It is necessary to take account of the needs of Christians there" in Saudi Arabia, he added.
Twelve years on and those words still ring true for the Vatican which continues to lament the lack of religious freedom in Saudi Arabia, the birthplace of Islam and the site of two of its holiest sites, Mecca and Medina.
While no precise figures exist on the religious denomination of the some eight million mostly Asian and African foreign guest workers in the kingdom, according to the Philippines government, some 90 per cent of the 1.2 million Filipinos who form part of this contingent are Catholic.
Christians, like other non-Muslims, are not only denied places of worship but also face arrest if found in possession of religious books and symbols.
Last month, Cardinal Jean-Louis Tauran, who as President of the Pontifical Council for Interreligious Dialogue is the Vatican's top official for dealing with Islam, reiterated what he said was the Holy See's willingness to reach out to Muslims.
Without specifically mentioning Saudi Arabia with which the Vatican does not have formal diplomatic relations, he also suggested something was expected in return.
"In a dialogue among believers, it is fundamental to say what is good for one is good for the other. For example, we must explain to the Muslims that if they can have mosques in Europe, it is normal that churches can be built in their countries," Tauran was quoted as saying in an interview with the French Catholic newspaper, La Croix.
Tuesday's scheduled meeting in the Vatican, the first between a pope and a Saudi monarch - a position that carries the Islamic title, Custodian of the Holy Sites - is important for its symbolism, according to Mario Scajola who heads the Italian branch of the Saudi- based World Muslim League.
The meeting which comes at the behest of Abdullah is an example of his "illuminated reign," Scajola, a former Italian ambassador to Saudi Arabia who converted to Islam in 1987, told Deutsche Presse- Agentur dpa.
Since the king succeeded to the throne in August 2005 following the death of his half-brother Fahd, he has introduced reforms including elevating women to important positions in the business and diplomatic fields, Scajola said.
This is in a country where women are not allowed to drive and are only granted legal status through their husbands or a male relative.
But an accord on non-Muslims practicing their faith in Saudi Arabia, "where this is banned but tolerated in practice," Scajola insisted, was "difficult" he said, referring to the possible outcome of the meeting between Benedict and Abdullah.
"It is not for me to tell the Saudi king what he should do, but in accordance with the teachings of the Koran I am personally in favour of religious freedom," Scajola said.
Speaking on condition of anonymity a Catholic priest who says he has visited Saudi Arabia clandestinely told dpa Tuesday's scheduled meeting was "pretty remarkable."
However, he believes the talks would not have a major impact on conditions faced by Christians in Saudi Arabia where non-Muslim religious services are also prohibited from being held inside foreign embassies.
"When we tell the Saudis: 'Look, we allow you to build a mosque in Rome, why won't you allow us to build churches in Saudi Arabia?' the standard reply is: 'Yes, but that would be like building a mosque in the Vatican,'" the priest said.
Still, whatever practical objectives Abdullah's visit to the Vatican achieves, it offers Benedict an opportunity to be seen engaging in dialogue with a top representative of Islam, the world's second largest religion after Christianity.
The pope opened a wound in September 2006 during a trip in his native Germany when during a speech he appeared to associate Islam with violence, sparking protests, in many cases violent, by Muslims around the world.
The pontiff has since somewhat made amends. First by stating that his words had been misinterpreted and that he meant no disrespect to Muslims, then by a visit last November to Turkey where he stopped to pray in Istanbul's main Blue Mosque becoming the second pope after John Paul II to enter a Muslim house of worship.
On Tuesday he may have another chance to show the world his intention to heal relations with Islam.
