According to the documents from Vatican archives relating to the trials of Jews, Muslims, Cathars, witches, scientists and other non-Catholics in Europe between the 13th and the 19th centuries, the number actually killed or tortured into confession during the Inquisition was far fewer than previously thought.

Estimates of the number killed by the Spanish Inquisition, which Sixtus IV authorised in a papal bull in 1478, have ranged from 30,000 to 300,000. Some historians are convinced that millions died.

But according to Professor Agostino Borromeo, a historian of Catholicism at the Sapienza University in Rome and curator of the 783-page volume released yesterday, only 1% of the 125,000 people tried by church tribunals as suspected heretics in Spain were executed.

Other experts told journalists at the Vatican yesterday that many of the thousands of executions conventionally attributed to the church were in fact carried out by non-church tribunals.

What the church initiated as a strictly regulated process, in which torture was allowed for only 15 minutes and in the presence of a doctor, got out of hand when other bodies were involved.

The church does not deny its responsibility for atrocities committed by Catholics in its name. In 2000 the Pope publicly apologised for the unnecessary "violence" used.

But he is not keen to be made to repent for sins the Vatican can prove it did not commit.

"Before seeking pardon, it is necessary to have a precise knowledge of the facts," he wrote in a letter released yesterday, in which he expressed his "strong appreciation" of the research.

"The image of the Inquisition represents almost the symbol ... of scandal," he wrote.

Cardinal Georges Cottier, a Vatican theologian, said: "You can't ask pardon for deeds which aren't there."

European and North American historians have been searching the archives since a Vatican conference on the Inquisition in 1998.

Their findings support the recent theories of some independent historians that the Spanish Inquisition has been exaggerated into a kind of legend.

European school histories are filled with images of torture used to force heretics to confess in Spain, France, Italy and Portugal.

Pope Gregory IX instituted the papal inquisition in 1231 for the apprehension and trial of heretics, initially the Cathars.

Inquisitors sought out those with hidden heretic beliefs as well as anyone reading banned books or teaching non-Catholic beliefs.

In 1633 the Italian scientist Galileo Galilei was imprisoned for expounding the Copernican theory that the Sun is the centre of the universe and the Earth rotates around it.

The theory was formally declared a heresy. Galileo died under house arrest.