LONDON — At first sight, Pope Benedict XVI’s approach to Islam may seem to diverge very little from his predecessor.

A scholar who has made an extensive study of the faith, the present pope is clearly keen to promote understanding between Christians and Muslims and has many personal contacts.

At his inaugural Mass as pope in April last year, he made a point of welcoming Islamic leaders.

In reality, however, Benedict XVI has adopted a far more cautious approach than the late John Paul II, who apologized for the Crusades and became the first pope to visit a mosque during a visit to Syria in 2001.

Even before he became pope, Cardinal Josef Ratzinger was a rigorous analyst of the theological differences between Christian and non-Christian faiths, and Islam in particular.

He is therefore less enthusiastic than his predecessor for interfaith summits such as that staged by John Paul II at Assisi, which critics fear can blur the distinctions between religions and diminish the status of Catholicism.

Since Benedict XVI became the pontiff, the Vatican has signaled a tougher line in its negotiations with Islam, stressing the need for “reciprocity.”

Vatican officials argue that if Muslims want the freedom to practice their faith in the West, Christians should be free from persecution in Islamic countries.

In the 1997 book “Salt of the Earth,” based on interviews with a German journalist, the then-Cardinal Ratzinger voiced mixed views of Islam.

On the one hand, he expressed admiration for the self-belief of the increasingly confident faith, which he saw as a potential ally in his war against relativism in the West.

But he was critical of Islam’s impulses toward theocracy, which he sees not as distortions but part of what he calls its “inner nature.”

A potential battleground is Europe, and Benedict XVI has irked many Muslims by arguing against Turkey’s membership of the European Union, which he fears could dilute Europe’s Christian roots.

The clearest indication of the pope’s change of emphasis was the sidelining of one of the Vatican’s leading experts on Islam, the British archbishop Michael Fitzgerald, who was closely associated with John Paul II’s policy of reconciliation.

Archbishop Fitzgerald, an Arab speaker and scholar, could have expected a Cardinal’s hat as head of the Vatican department dealing with interreligious dialogue.

Instead, as part of a shake-up of the Curia last year, he was dispatched to Cairo as the pope’s envoy in a move widely seen as a demotion.

At the time, Vatican watchers expressed alarm.

Father Thomas Reese, a Jesuit, said at the time: “The Pope’s worst decision so far has been the exiling of Archbishop Fitzgerald. He was the smartest guy in the Vatican on relations with Muslims. You don’t exile someone like that, you listen to them. If the Vatican says something dumb about Muslims, people will die in parts of Africa, and churches will be burned in Indonesia.”