The historic spectacle included four kings, five queens and more than 70 prime ministers and presidents, reports
President Bush and French President Jacques Chirac — divided over the U.S.-led war in Iraq — were separated only by their wives as they sat in the second row to the right of the altar in front of St. Peter's Basilica.
Farther down the same row was Iranian President Mohammad Khatami, who greeted Syrian President Bashar Assad before taking his seat. Washington has tense relations with Syria and none with Iran.
During the funeral Israeli President Moshe Katsav shook hands with the leaders of Israel's archenemies, Syria and Iran, Katsav's office said — twice with Assad.
"During the prayers, according to the Christian tradition we exchanged handshakes ... During this, it was the Syrian president who extended his hand to me and we again shook hands," Katsav told the Web site of the Maariv daily.
The Iranian-born Katsav also spoke briefly with Khatami in Farsi and reportedly embraced Algerian President Abdelaziz Bouteflika. Israel, which beefed up its delegation overnight to included Katsav, does not have relations with any of the countries.
More than 100 official delegations attended the funeral, one of the largest religious gatherings of modern times. The seating plan was drawn up using French, the traditional language of diplomacy.
Just making it onto the front row was King Juan Carlos of Spain — Espagne — ahead of the president of the United States — Etats-Unis — in the second.
One row back from Mr. Bush and Chirac was Zimbabwe President Robert Mugabe, just two places away from Britain's Prince Charles. Mugabe sidestepped a European Union travel ban — which does not apply to the Vatican — to attend the funeral.
Charles had originally been planning to wed Camilla Parker Bowles on Friday, but pushed back the marriage by a day.
Before the service, leaders filed out from between the crimson curtains framing the giant bronze doors of St. Peter's. They shook hands with a prelate, paused to exchange greetings, then took their seats.
The gathering made for a rare display of religious plurality: scarlet-robed Roman Catholic cardinals, black-clad Orthodox clerics, Arab head scarves, Jewish skull caps, Central Asian lambskin hats, and black veils worn by some women.
Chirac leaned over earnestly to make a comment to U.N. Secretary General Kofi Annan, who appeared to listen attentively. Khatami, dressed in a black turban and round tinted glasses, kissed Assad on both cheeks.
Mr. Bush was one of the last to file out of the Basilica to take his place, walking with his wife Laura and ahead of his father, former President George H.W. Bush, former President Bill Clinton and Secretary of State Condoleezza Rice.
The funeral had already sparked diplomatic tensions. China announced Thursday that it would not send a delegation to the funeral due to the Vatican's diplomatic relations with rival Taiwan, whose president, Chen Shui-bian, took advantage of a rare chance to meet other leaders at an international event.