Given the potential for it all to go so terribly wrong, many are wondering why the Pope has gone ahead with his visit to Turkey this week.

Even the would-be assassin of the last Pope has written to Benedict XVI from his prison cell, warning him that his life is in danger. And if the Pope himself, protected by bodyguards and his armoured car, does come through unscathed, many others might be not be so lucky should violence does erupt around the four-day visit.

Innocent lives, including that of a nun, were lost in the aftermath of his notorious Regensberg address. It is not enough to argue that Islam shows itself in extremis to be guilty of the very faults the Pope was criticising when such people die in protests committed in its name.

Lives lost in such a manner are lives tragically wasted, whether these deaths prove a point or not. Even the Pope himself, making his last preparations for the visit yesterday, said: "I am worried, however, am sure that this visit is very necessary."

He is not the first Pope in modern times to visit the democratic, secular state. Pope John Paul II went in 1979. Paul VI also went, and John XXIII served in Istanbul as apostolic delegate. But the world when Benedict's predecessor visited the Ecumenical Patriarchate, the "first among equals" in the Orthodox world, was incomparably different.

The decline of religion was confidently forecast and the big threat on the horizon was communism. Even until recently, Islam and Catholicism were regarded as marching hand-in-hand against secularism, not each other.

The extent of the seismic shift that took place in this relationship on 9/11 only became clear after Regensberg, when he quoted from Byzantine Emperor Manuel II who alleged in 1391 that the prophet Muhammad promoted "things only bad and inhuman, such as his command to spread by the sword the faith his preached."

Moderate Muslims are among those who fear that the Pope might unwittingly have launched a modern crusade. It is that fear, with all its historic anxieties and stresses adding to the toxic mix of the secular and religious in modern Turkey, that underlies many of the protests witnessed in the last few days.

The highlight of the apostolic journey to Turkey will be on Thursday, the feast day of St Andrew the Apostle, St Andrew was brother to Rome's St Peter. St Andrew, also patron saint of Scotland, is known in the Orthodox Church as Protokletos, or "first called". When Christ's Apostles drew lots as to where they should go to spread the word, he got Asia Minor, which would have included Constantinople.

On Thursday, the Pope will join the Ecumenical Patriarch, Bartholomew, at Divine Liturgy to mark the festival. Developing relations with the Orthodox is one of the main goals of his papacy, in line with his pursuit of full Christian unity, mentioned as one of his priorities in his homily delivered address in the Sistine Chapel the day after his election last April.

Another objective of the visit is to give succour to the tiny Catholic community, which numbers about 32,000 among the country's 72 million inhabitants. The Catholic Church is not officially recognised in Turkey, where 99 per cent of the population is Muslim.

But since Regensburg, the third objective, of fostering dialogue with Islam, has assumed a new imperative.

Ultimately, the outcome could be positive. In his former incarnation as Cardinal Joseph Ratzinger, the Pope voiced opposition to Turkey entering the European Union.

The Vatican has made it clear this week that it is not opposed. Many in Turkey fear its identity as a secular state is under threat and if Europe cools on admitting its new neighbour, it will have itself to blame if Turkey looks eastwards instead.

By agreeing to meet the Pope, the Turkish Prime Minister lit a spark of hope. It would be a welcome irony if his endeavours to undo the harm caused by Regensberg led him to become Turkey's champion, ultimately easing its admission to Europe, and proving that both Islam and Catholicism can in the 21st century remain true to their traditional aspiration of hospitality towards each other.

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