With the agreement of the Pope himself, Agca was pardoned by the Italian president on Tuesday after serving 19 years of a life sentence.

This is a dream - I cannot believe it

Mehmet Ali-Agca

Escorted onto a plane in Italy by representatives of the Turkish police, Agca was met in Istanbul by armoured cars and police convoys who whisked him away to jail to serve a sentence for a crime that pre-dates his attempt to kill the Pope.

In a statement distributed by his Italian lawyer, Agca described his return to Turkey as a dream come true.

Criminal past

"Once I've paid my debt to the Turkish legal system," he said, "I want to retire far from the noise which has dominated my life."

Turkish police escorted Agca onto the plane

Before he tried to assassinate the Pope in 1981, Agca was convicted of killing one of Turkey's leading journalists, Abdi Ipekci, in 1978.

He escaped from prison while awaiting trial for that crime but was sentenced in absentia.

The Justice Minister says he must now serve the remaining nine and a half years of his jail term.

Clemency

Chief Vatican spokesman Joaquin Navarro-Valls said that the Pope welcomed the pardon: "He has been insisting on this for some time."

The attempt on the Pope's life - on 13 May 1981, less than three years after his accession to the Papacy - came as he drove across Saint Peter's Square in an open car to hold a general audience with a crowd of 20,000 people.

The Pope narrowly escaped death 20 years ago

He was hit by three bullets - one entered his stomach, another hit his left hand and the third his right arm.

Two of his aides were also injured in the attack. Mr Agca was arrested by Italian police as he tried to flee the scene and sentenced to life imprisonment.

The Pope later publicly forgave Mr Agca and even visited him in prison, but the Vatican said it would not stand in the way of Italian justice in the case.

Mystery

Despite three investigations and two trials, mystery has long surrounded the assassination attempt.

It was at first believed to be linked to Bulgarian and Soviet secret services as part of a communist plot to kill the Pope, who helped to loosen the grip of communist authorities in his Polish homeland.

However, at the second trial in 1986, prosecutors failed to prove charges that Bulgarian secret services had hired Mr Agca on behalf of the Soviet Union.