Buddhist chants and Christian hymns resounded inside a huge plastic tent decorated with a single olive tree, a symbol of peace, in the home of St. Francis, the medieval monk associated with peace.
About 200 religious leaders accepted the pope's invitation to the daylong retreat and agreed on a joint, 10-point pledge that proclaims that religion must never be used to justify violence.
John Paul, looking down at a display of turbans, veils and yarmulkas from a red-carpeted stage, said religious leaders must fend off ``the dark clouds of terrorism, hatred, armed conflict, which in these last few months have grown particularly ominous on humanity's horizon.''
He called it ``essential'' that religious people ``in the clearest and most radical way repudiate violence, all violence, starting with the violence that seeks to clothe itself in religion.''
``There is no religious goal which can possibly justify the use of violence by man against man,'' the pope declared.
It was one of the largest gatherings ever of Christian groups, bringing together Catholics, Baptists, Lutherans, Quakers, Mennonites, among others, as well as Orthodox Christians, headed by the ecumenical patriarch, Bartholomew I.
They joined representatives of 11 other religions: Judaism, Islam, Hinduism, Buddhism, Shintoism, Jainism, Confucianism, Sikhism, Zoroastrianism, and followers of Tenrikyo and African tribal relgions.
The Christians prayed together in the frescoed Lower Basilica of St. Francis, restored after a powerful 1997 earthquake. Others were accommodated in separate the brick cells of nearby convent near the tomb of St. Francis, with crosses and other religious objects removed for the occasion. Muslims knelt on rugs and prayed in Arabic in a room facing Mecca.
One of the Muslim representatives, Ali el Samman, representing the grand sheik of Cairo's Al-Azhar mosque and Islamic university, concluded his remarks by thanking the Vatican for its ``honorable support of the Palestinian people.''
Rabbi Israel Singer, head of the governing board of the World Jewish Congress, was the only non-Christian to speak of the Sept. 11 attack, describing it as the work of ``madmen who claimed to be acting in the name of religion.''
Singer said it was essential to obtain peace for ``all of us'' to answer the question ``whether land or places are more important than people's lives.''
``Peace is too important to be left to the generals,'' he said.
Assisi has twice before hosted papal prayer days: a daylong fast and prayer against nuclear war in 1986 and a rally for Balkan peace in 1993.
John Paul traveled to and from Assisi on what the Italian media dubbed the ``train of prayers,'' bringing the religious leaders with him on a two-hour trip from the rarely used train station in the Vatican and back.
Italy's state railroad gave the Vatican a seven-car train, each car bearing the Vatican's coat of arms.
About 1,000 police were deployed along the route, and two police helicopters flew low overhead. Italian media said the ancient town would be sealed off for the duration of the ceremony.
The pope, who suffers from the symptoms of Parkinson's disease, appeared in fine form throughout the day, playfully waving his cane to the crowds as he left Assisi under a steady rain.
``He was positively glowing,'' said Rabbi Ron Kronish, director of the Interrelgious Coordinating Council in Israel. ``He had so much spiritual energy. He sort of radiated it to everyone.''
Among the leaders attending the retreat was Cardinal Edward Egan, archbishop of New York, the site of the Sept. 11 attacks. He called the event an attempt by the pope to ``alert the world to the need to put an end to the conflict that is troubling us right now.''
``Coming from New York, I am especially concerned,'' Egan told reporters on the papal train.
Asked about Italian press reports that the pope would like to visit ``ground zero'' of the World Trade Center while visiting North America in July, Egan replied ``I'm sure they'll tell me sometime soon if it is true.''
The pope's itinerary currently does not include a stop in New York.
Imam Mahmoud Hammad Ibrahim Sheweitah, a member of the Muslim delegation from Italy, was asked by reporters on the train whether Sept. 11 suspect Osama bin Laden was a good Muslim.
``We don't know. Because we only know about him from television,'' he replied. He said ,however, that good Muslims could not be terrorists.
Kronish said he was going home ``spiritually empowered'' by the day's events, even though he acknowledged it would be difficult to know whether the event was a success.
``Does it resolve anything tomorrow? No it doesn't. Will it have impact in the long run? I hope so,'' he said.