VATICAN CITY (AP) — Pope Francis honored his predecessor Benedict XVI, the German theologian who made history by retiring, presiding Thursday over a rare requiem Mass for a dead pontiff by a living one before thousands of mourners in St. Peter’s Square.

Bells tolled and the faithful applauded as pallbearers carried Benedict’s cypress coffin out of the fog-shrouded basilica and rested it before the altar. Benedict’s longtime secretary, Archbishop Georg Gaenswein, bent down and kissed a book of the Gospels that was left open on the coffin.

Francis, wearing the crimson vestments typical of papal funerals, then took his place and opened the Mass with a prayer,

Heads of state and royalty, clergy from around the world and thousands of regular people flocked to the ceremony, 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.

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

After some 200,000 people paid their respects during three days of public viewing, authorities estimated some 100,000 would attend Benedict’s funeral, though it was not clear if that many did in the end.

Only Italy and Germany were invited to send official delegations, but other leaders took the Vatican up on its offer and come in their “private capacity.” They included several heads of state, at least four prime ministers and two delegations of royal representatives. In addition, a host of patriarchs joined 125 cardinals in the seats to the side of the altar.

Among them was Hong Kong Cardinal Joseph Zen, who was given special court permission to attend the funeral and arrived in Rome on Thursday. Zen was detained in May on suspicion of colluding with foreign forces under a national security law that China after he fell afoul of authorities over his participation in a now-silenced democracy movement. His passport was revoked when he was detained.

Matteo Colonna, a 20-year-old seminarian from Teramo, Italy, said he came in part because of the historic nature of the funeral — but also because it had personal resonance for him.

“The first spark of my vocation started under the pontificate of Benedict, but then it became even stronger under Pope Francis,” Colonna said, while sitting in prayer in St. Peter’s Square ahead of the funeral. “I see a continuity between these two popes and the fact that today Francis is celebrating the funeral in Benedict’s memory is an historical event.”

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.”

Francis didn’t dwell on Benedict’s specific legacy in his homily and only uttered his name once, in the final line, delivering instead a meditation on Jesus’ willingness to entrust himself to God’s will.

“Holding fast to the Lord’s last words and to the witness of his entire life, we too, as an ecclesial community, want to follow in his steps and to commend our brother into the hands of the Father,” Francis said at the end.

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.

A group representing German clergy abuse survivors called on German officials attending Benedict’s funeral to demand more action from the Vatican on sexual abuse. Eckiger Tisch asked German leaders to demand that Francis issue a “universal church law” stipulating zero tolerance in dealing with abuse by clergy.

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

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 will 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 unusual, 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.

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.