His final journey was testimony to his life on the world stage as the throngs pressed to capture a glimpse as the Swiss guards in their blue, red and yellow livery solemnly marched by.
Television cameras beamed the scenes of the procession to a global audience and many in the square captured an image on their mobile cameras.
Before turning into the basilica, the palanquin carrying the Pope’s body was turned toward the square where the Pope had presided on countless occasions during his 26-year reign as head of the Roman Catholic Church.
The Pope’s body will lie in state for three days and nights until the funeral which is set to become one of the largest gatherings of world leaders in history.
Viewing of the body will be possible virtually around the clock, except for a couple of hours overnight.
The Vatican has announced the Pope would be buried on Friday and would be interred in the crypt of St Peter’s basilica in line with tradition, rather than his native Poland as many Poles had hoped.
Friday’s funeral is set to draw up to two million mourners, officials say, as well as around 200 foreign leaders including US President George W Bush.
Hundreds of millions more will follow the ceremony on television across the world.
Announcing details of the funeral arrangements, Vatican spokesman Joaquin Navarro-Valls said the requiem mass at 10 am (0800 GMT) would be celebrated by Cardinal Joseph Ratzinger, the Vatican’s doctrinal enforcer and a possible successor to John Paul II.
However, the cardinals did not name a date when they would meet for their closed-door conclave to begin the process of electing a successor.
Under Vatican rules, their sequestration cannot begin until at least 15 days after the Pope’s death, which would be April 17.
John Paul II’s death has drawn eulogies around the world for his commitment to peace, humanity and dialogue.
He is credited with having contributed to the fall of communism in Poland and by extension the whole of eastern Europe.
Tributes have continued to pour in.
South African former president and anti-apartheid icon Nelson Mandela said the Pope had offered “moral direction and guidance” in a fast-moving but uncaring world.
“The world is undoubtedly a better one for the legacy and the teaching he leaves behind,” Mr Mandela said in a statement.
Around the world, Christians and people of other faiths prayed, mourned and paid tribute to a Pope seen as transcending religious barriers.
In his native Poland and across Europe, in the Middle East, Africa and the Americas, special masses were said, vigils kept and candles burned.
In the United States, flags flew at half-mast on public buildings, and even the freewheeling NASDAQ stock market in New York held a moment of silence when dealers, who work mainly on computer screens, were asked not to trade.
But a discordant note was sounded when AIDS campaigners notably slammed the Pope’s ban on condom use, abhorrence of homosexuality and conservatism on women’s rights as bleak failures in the fight against HIV.
Inside the Church, the reform movement ‘We Are Church’ listed a slew of “human rights” demands for the next pontiff: women’s ordination, the right of priests to marry, freedom of conscience and the right to be respected for one’s sexual orientation.
President Bush, who clashed with the pope over the war on Iraq, will be the first US president to attend a papal funeral.
“It is my great honour on behalf of our country to express our gratitude to the Almighty for such a man,” he told reporters.
Other leaders confirmed as attending include UN chief Kofi Annan, British Prime Minister Tony Blair, French President Jacques Chirac, President Gloria Arroyo of the Philippines and the presidents of Brazil, Poland and Syria.
Security will be extremely tight. Italian authorities are deploying up to 10,000 military and police personnel, with warplanes, helicopters and a NATO surveillance plane enforcing a no-fly zone over the capital.
The Pope’s death has already obliged Prime Minister Blair to delay an announcement of the British general election, which he had been due to make Monday, by a day.
The vote is widely expected for May 5.
Amid the grieving and commemorations, speculation bubbled along as to who will succeed John Paul II.
An Irish bookmaker has put cardinals Francis Arinze of Nigeria and Dionigi Tettamanzi of Italy at the top of its list of likely successors, followed by Honduran Oscar Rodriguez Maradiaga, Germany’s Ratzinger and Claudio Hummes of Brazil.