ATHENS, May 5 (Reuters) - Pope John Paul on Saturday ended a landmark trip to Greece that may prove a turning point in relations with the Orthodox Church and flew to Syria, where he was to appeal for Middle East peace.
The Pope left Athens after a mass in which he appealed to about 15,000 people representing Greece's tiny Roman Catholic community of some 200,000 to work for Christian unity.
The Catholics had asked to use the Olympic Stadium, saying they could fill its 80,000 seats, but were told that, for security reasons, they could have only the much smaller Olympic basketball court.
The 80-year-old Pope was on day two of a six-day pilgrimage in the footsteps of St Paul the Apostle.
At the mass, he said all Christians should show "passion" for eventual unity between all branches of Western and Eastern Christianity.
"We take with us the sad heritage of the past...there is still a long way to go," he said.
On Friday he had asked forgiveness for the wrongs done by Roman Catholics to Orthodox Christians since the Great Schism of 1054 split the Church into eastern and western branches.
"May the memory of the time the Church breathed with both lungs spur Christians of the East and West to walk together in unity of faith and with respect for legitimate diversity," he said in a homily.
The historic apology followed a harangue by the head of the Greek church, Archbishop Christodoulos, who had only grudgingly agreed to the papal visit.
"WE BEG FORGIVENESS"
"For occasions past and present, when the sons and daughters of the Catholic Church have sinned by actions and omission against their Orthodox brothers and sisters, may the Lord grant us the forgiveness we beg of him," the Pope said.
Many Orthodox blame the Catholic church for a litany of offences, from the Great Schism itself to the Fourth Crusade, in which the Byzantine capital Constantinople was sacked in 1204.
In his request for forgiveness, the Pope specifically mentioned the sacking of Constantinople.
The two men later sat on the hill where the apostle preached to ancient Athenians and issued a joint statement calling for an end to violence in the name of religion.
Vatican spokesman Joaquin Navarro-Valls said on Saturday that at a third meeting, the archbishop and the Pope had said the Lord's Prayer together -- a change of heart by Christodoulos, who had earlier publicly ruled it out.
Greek newspapers hailed the Pope's plea for forgiveness as a breakthrough in attempts to thaw relations.
"Papal apology reverses history," read the headline in the daily Ethnos.
In Syria, the Pope was due to appeal for peace from the Golan Heights town of Quneitra, which Israel captured from Syria in the 1967 Six Day War and returned in 1974.
His arrival in Damascus will mean he has visited Israel and all bordering nations that have been at war with it.
After four days in Syria, the Pope ends his trip in predominantly Catholic Malta, presiding at a beatification ceremony for two Maltese priests and a nun.