Pope Benedict XVI is being laid to rest on Thursday, with the funeral unusually being presided over by his successor, Pope Francis.

Francis celebrated Mass in St. Peter's Square before his German-born predecessor was entombed in the papal tombs beneath St. Peter's Basilica.

A large crowd, some of whom had gathered at the crack of a misty dawn outside the building, sang hymns and listened to readings as the ceremony began at around 9:30 a.m. local time (0830 GMT/UTC). The Vatican said roughly 50,000 people attended in all.

Mourners from Benedict's native Bavaria, dressed in traditional garb, were present among the crowds.

"Benedict, faithful friend of the bridegroom [a reference to Jesus — editor's note], may your joy be complete as you hear His voice, now and forever," Francis concluded a short speech in which he had commended his predecessor.

Francis spoke to the thousands of other Catholic clergy members of the "wisdom, tenderness and devotion that he [Benedict] bestowed upon us over the years."

The pope also appeared at several points to paraphrase biblical references to Jesus while alluding to Benedict, including saying that "love means being ready to suffer." 

The pope, who has been in poor health and was brought to the ceremony in a wheelchair, stood briefly and said a prayer over the coffin before it was removed.

A prayer in German followed Francis' address, as prayers were then delivered in multiple languages, in a bid to show the Church's global reach. 

Archbishop Georg Gänswein, Benedict's long-serving personal secretary and confidant, kissed the coffin amid the ceremony. 

First pope emeritus in centuries

Pope Emeritus Benedict XVI died in Rome on Saturday, aged 95.

Benedict, the former Cardinal Joseph Ratzinger, became the first German pope in centuries when he was elected in 2005.

In 2013, he became the first pontiff in six centuries to resign, citing his frail health. His eight-year tenure was marred by the fallout from the global sex abuse scandal that has rocked the Catholic Church.

The Vatican made mention of this, albeit in an optimistic tone, in its document honoring the theologian's tenure as pope that will be buried with Benedict. 

"He battled determinedly against the crimes that were committed by representatives of the clergy on minors and people in need of protection, and repeatedly called the church to conversion, to prayer, to repentance and to cleansing," the document read, according to a release from the Holy See in Latin and Italian.

What are the other plans for Thursday's ceremonies? 

According to the Vatican, Benedict had requested a comparatively modest ceremony, though several papal traditions were still upheld such as a three-coffin burial. 

After lying in state in St. Peter's Basilica, his body was moved into a cypress coffin, to prepare him for the funeral, which is expected to be attended by around 100,000 people, including heads of state and government, European royals and 3,700 members of the clergy.

A written account of his time as pope in a metal cylinder and coins minted at the Vatican during his tenure was to be placed with the body. 

The body was then be carried to St. Peter's Square where Pope Francis said a Mass with readings in several languages. 

After the funeral, the body was returned to the basilica for a private ceremony and the coffin was encased in another made of zinc and then a larger one made of wood.

Benedict was then interred in the Vatican Grottoes, a site underneath St. Peter's Basilica that houses some 90 deceased popes. These included the remains of his predecessor, Pope John Paul II, until his tomb was moved into the main part of the basilica after he was beatified, or turned into a saint by the Church. Benedict's coffin will be placed in John Paul II's old position.

Full complement of German, Bavarian political dignitaries

The body of the former pope had laid in state for three days.

People began gathering outside the basilica at dawn on Monday before the doors opened. Thousands were allowed to view the body and pay their respects for several hours.

Benedict's funeral will be marked in his home country with church bells ringing at 11 a.m local time (1000 GMT/UTC).

German Chancellor Olaf Scholz will also attend the funeral. Formal state invitations were only issued to officials from Italy and Germany, though leaders from several other countries will attend in a private capacity.

On the German side, all five heads of the various state organs have jetted off to Rome. President Frank-Walter Steinmeier, the presidents of the two houses of parliament, Bärbel Bas of the Bundestag and Peter Tschentscher of the Bundesrat, and even the top judge on the constitutional court, Stephan Harbarth, will all attend besides Scholz. 

Meanwhile, Bavarian state premier Markus Söder of the Christian Social Union (CSU) led a delegation to Rome from Ratzinger's home state.

"Meeting with the federal president in Rome," Söder wrote on Twitter, sharing an image of him and Steinmeier shaking hands and exchanging pleasantries. "Like me, it is his birthday today. All the best, Frank-Walter Steinmeier. Sadly it's nevertheless an odd feeling on a day like today..."

msh, rmt/wmr (AFP, AP, dpa, Reuters)