Pope Benedict XVI will on Monday mark five years at the helm of a Roman Catholic Church deep in crisis over its handling of a series of paedophile priest scandals.

The Vatican's laments of being unfairly targeted for attack, combined with statements or initiatives seen as half-measures - as well as outright gaffes - have weakened the Pontiff, analysts say.

And Pope Benedict, who turned 83 yesterday, has already built up a reputation of seeming insensitivity on other issues.

The German Pontiff has repeatedly angered Jews since his election in 2005, notably by lifting the excommunication of traditionalist bishop Richard Williamson, who insists that no there were no Nazi gas chambers.

But he has also found himself in hot water with Muslims, native Indians, Poles, gays and even scientists.

"In the modern era, there has never been a pontificate marked by such cyclical crises that have become continual by now," said Vatican expert Marco Politi of the left-wing Italian newspaper Il Fatto Quotidiano.

Of them all, the furore over child-molesting priests is by far the most damaging because "the crimes committed by many clergymen were covered by the silence of Church authorities," Mr Politi said.

"These are not isolated crimes, but an institutional sin of silence," Mr Politi said.

He praised Pope Benedict for a letter to Irish Catholics last month in which the pontiff rebuked the nation's bishops for making "serious mistakes" in responding to allegations.

However, Mr Politi said: "Because many of his choices have provoked crises, Pope Benedict has shattered the Catholic world, and today the Church is very divided, even if it doesn't really show.

"The Papacy has lost its ability to attract and the influence on public opinion that it had during the time of John Paul II," Mr Politi said.

Another Vatican watcher, John Allen of the National Catholic Reporter, said: "In terms of business management, this pontificate goes from one crisis to the other."

Pope Benedict found himself in his first full-blown crisis in September 2006 when he unleashed fury in the Muslim world with a speech in which he appeared to endorse the