VATICAN CITY — Mourners poured into St. Peter’s Square early Thursday for the funeral of Pope Emeritus Benedict XVI to pay their final respects to the German theologian who made history by retiring and to attend a rare requiem Mass for a dead pontiff presided over by a living one.

Bells tolled and the crowd applauded as pallbearers carried Benedict’s cypress coffin out of the basilica and rested it before the altar in the piazza, as red-robed cardinals looked on.

Heads of state and royalty, clergy from around the world and thousands of faithful flocked to the Vatican, despite Benedict’s requests for simplicity and official efforts to keep the first funeral for an pope emeritus in modern times low-key.

Many hailed from Benedict’s native Bavaria and donned traditional dress, including boiled wool coats to guard against the morning chill.

“We came to pay homage to Benedict and wanted to be here today to say goodbye,” said Raymond Mainar, who traveled from a small village east of Munich for the funeral. “He was a very good pope.”

The former Joseph Ratzinger, who died Dec. 31 at age 95, is considered one of the 20th century’s greatest theologians and spent his lifetime upholding church doctrine. But he will go down in history for a singular, revolutionary act that changed the future of the papacy: He retired, the first pope in six centuries to do so.

Pope Francis has praised Benedict’s courage to step aside, saying it “opened the door” to other popes doing the same. Francis, for his part, recently said he has already left written instructions outlining the conditions in which he too would resign.

Francis was due to preside over the funeral, which authorities estimated some 100,000 would attend, higher than an original estimate of 60,000, Italian media reported, citing police security plans.

Only Italy and Germany were invited to send official delegations, but other heads of state and government took the Vatican up on its offer and come in their “private capacity.” They included several other heads of state, at least four prime ministers and two delegations of royal representatives.

Early Thursday the Vatican released the official history of Benedict’s life, a short document in Latin that was placed in a metal cylinder in his coffin )before it was sealed, along with the coins and medallions minted during his papacy and his pallium stoles.

The document gave ample attention to Benedict’s historic resignation and referred to him as “pope emeritus,” citing verbatim the Latin words he uttered on Feb. 11, 2013, when he announced he would retire.

The document, known as a “rogito” or deed, also cited his theological and papal legacy, including his outreach to Anglicans and Jews and his efforts to combat clergy sexual abuse “continually calling the church to conversion, prayer, penance and purification.”

The funeral ritual itself is modeled on the code used for dead popes but with some modifications given Benedict was not a reigning pontiff when he died.

After the Mass, Benedict’s cypress coffin was to be placed inside a zinc one, then an outer oak casket before being entombed in the crypt in the grottos underneath St. Peter’s Basilica that once held the tomb of St. John Paul II before it was moved upstairs.

While the ritual is novel, it does have some precedent: In 1802, Pope Pius VII presided over the funeral in St. Peter’s of his predecessor, Pius VI, who had died in exile in France in 1799 as a prisoner of Napoleon.

Some 200,000 paid tribute to Benedict during three days of public viewing in the basilica, with one of the last, Friar Rosario Vitale, spending an hour praying by his body. He said Benedict had given him a special dispensation to begin the process of becoming a priest, which was required because of a physical disability.

“So today I came here to pray on his tomb, on his body and to say ‘thank you’ for my future priesthood, for my ministry,” he said.

Benedict never intended his retirement to last as long as it did — at nearly 10 years it was longer than his eight-year pontificate. And the unprecedented situation of a retired pope living alongside a reigning one prompted calls for protocols to guide future popes emeritus to prevent any confusion about who is really in charge.

During St. John Paul II’s quarter-century as pope, Ratzinger spearheaded a crackdown on dissent as prefect of the Congregation for the Doctrine of the Faith, taking action against the left-leaning liberation theology that spread in Latin America in the 1970s and against dissenting theologians and nuns who didn’t toe the Vatican’s hard line on matters like sexual morals.

His legacy was marred by the clergy sexual abuse scandal, even though he recognized earlier than most the “filth” of priests who raped children, and actually laid the groundwork for the Holy See to punish them.

As cardinal and pope, he passed sweeping church legislation that resulted in 848 priests being defrocked from 2004-2014, roughly his pontificate with a year on either end. But abuse survivors still held him responsible for the crisis, for failing to sanction any bishop who moved abusers around and identifying him as embodying the clerical system that long protected the institution over victims.

“Any celebration that marks the life of abuse enablers like Benedict must end,” said the main U.S. survivor group SNAP.