Celebrations are taking place in Rome for the 400th anniversary of a Dominican monk whose execution is causing embarrassment to the contemporary church.

Giordano Bruno was burnt at the stake on 17 February, 1600, for refusing to recant his philosophical beliefs before the Catholic Church's Inquisition.

Bruno, who travelled throughout Europe writing and teaching, is seen by some historians as a forerunner of modern scientific thinking.

He expounded the theory that God was in all things and the universe was infinite.

But it was his defence of the ideas of Copernicus - saying the sun could not be the centre of that universe - that landed him in trouble with the Catholic church.

Anti-clerical hero

Bruno's resistance to church intolerance and his refusal to bend before authority have made him a symbol of freedom of thought and an anti-clerical hero in Italy.

Scholars, politicians, anarchists, anti-clerical and human rights groups are commemorating Bruno's life in a series of events.

Anarchist groups are reading his death sentence and performing street theatre, a local Rome school has adopted his statue and there will be a parade in his honour in historical costume.

Bruno and others tortured and killed by the Inquisition will receive a formal apology from the Catholic church next month.

Pope John Paul will publicly seek forgiveness for errors and injustices committed by the church in a "Request for Forgiveness Day."

No rehabilitation

But the monk is unlikely to be rehabilitated by the church.

Cardinal Paul Poupard, chairman of the Vatican's cultural council, has said Bruno's teachings are "incompatible" with Christian doctrine and it is not possible to rehabilitate him.

Bruno scholar Anacleto Verrecchia told Italian newspaper Corriere della Sera the Pope cannot rehabilitate the monk.

"Bruno's theory that the universe is eternal excludes the idea of a god creator and is probably closer to Buddhism," he said.