The cardinal was convicted in December 2018 of five charges of child sexual abuse relating to allegations he raped one 13-year-old and molested another at St Patrick's Cathedral in 1996.

He was the highest ranking member of the Catholic Church to be convicted of child sexual abuse.

In April 2020 he also became the highest ranking member to be acquitted.

Australia's High Court overturned the verdict of a jury and a 2-1 majority decision by Victoria's Court of Appeal to uphold it.

Though he didn't give evidence at either of two trials in the Victorian County Court - the first jury was unable to reach a unanimous verdict - Cardinal Pell maintained his innocence.

Six months after being freed he returned to the Vatican, where he died on Tuesday, aged 81.

He suffered complications from hip surgery.

Cardinal Pell, a VFL footballer before joining the priesthood, had undergone a double knee replacement in Victoria between court proceedings.

The High Court's decision and his death haven't changed public opinions of Cardinal Pell - a divisive figure to the end.

"Rot in Hell Pell" was emblazoned on the doors of the cathedral at the centre of the allegations after he was freed, while the words "the law protects the powerful" were spray painted on the forecourt.

"There's such strong emotions around all of these matters," Archbishop of Melbourne Peter Comensoli said at the time.

Cardinal Pell's surviving accuser, a man now in his 30s known as "J" said he hoped the outcome wouldn't dissuade other survivors of child sexual abuse from coming forward.

"Most people recognise the truth when they hear it ... I am content with that," he said in 2020.

His schoolmate, the other of Cardinal Pell's alleged victims, died in April 2014.

His father has a lawsuit pending in Victoria's Supreme Court against the Catholic Archdiocese of Melbourne and Cardinal Pell, claiming he suffered nervous shock after being informed of the alleged offending.

His lawyer, Lisa Flynn, said the claim would continue against the church and any estate left by Cardinal Pell.

She said a civil trial would have provided the opportunity to cross-examine him and "truly test his defence" but noted there was still evidence for the claim to rely upon.

The church tried to be excused from the trial, by arguing the man could not sue as he was not the direct victim. A judge dismissed this, allowing the civil trial to continue, but the case is on hold as the church is appealing.

It was alleged that, after a choir practice in 1996, Cardinal Pell had caught the two boys drinking wine in the priest's sacristy and exposed himself and abused them.

Cardinal Pell's barrister, Robert Richter, described the claims as a "far-fetched fantasy".

"Only a madman would attempt to rape boys in the priest's sacristy immediately after Sunday solemn mass," he told jurors.

In sentencing Cardinal Pell to six years behind bars in March 2019, County Court Chief Judge Peter Kidd described the offending as "brazen" sexual crimes.

"I am conscious that a term of imprisonment ... carries with it a real, as distinct from theoretical, possibility that you may not live to be released from prison," he said.

Then 77, the cardinal had appeared drained and slimmer after two weeks in custody. He sat emotionless and unflinching, minus his clerical collar for what was believed to be the first time in public since his 1966 ordination.

The sentence was handed down after a hearing featuring prominent voices - including a character reference from former prime minister John Howard.

Former deputy prime minister Tim Fischer, who was also Australia's first ambassador to the Vatican, had been in court for parts of the trial and former prime minister Tony Abbott visited Cardinal Pell behind bars.

"He relates to everyone from a prime minister to street beggars," Mr Richter had said.

Cardinal Pell said his trial was not a referendum on the Catholic Church or how Australian church authorities dealt with pedophilia.

"The point was whether I had committed these awful crimes and I did not," he said.

A second trial, involving allegations Cardinal Pell sexually abused two other boys - aged between nine and 12 - was discontinued by prosecutors in February 2019 after evidence crucial to their case was ruled inadmissible.

A month after his convictions were overturned, the full and unredacted report of findings from the Royal Commission into Institutional Responses to Child Sexual Abuse was released.

Cardinal Pell was among a large number of senior church officials who knew of complaints about abuse by numerous priests and Christian Brothers in the 1970s and 1980s, it found.

Among them was the cardinal's former housemate and Australia's most prolific paedophile priest, Gerald Ridsdale.

He was also found to have brushed off complaints by a young boy about Christian Brother Edward Dowlan's abuse of young boys as "ridiculous".

The inquiry rejected Cardinal Pell's claim he was deceived "in a world of crimes and cover-ups" about Ridsdale and others.

"We are also satisfied that by 1973 Cardinal Pell was not only conscious of child sexual abuse by clergy but that he also had considered measures of avoiding situations which might provoke gossip about it," the commissioners wrote in the final report.

Cardinal Pell gave evidence via video link from Rome, saying he regretted putting the church before victims in the past but had never put himself before either.

He admitted having heard rumours of abuse but told the inquiry he had no authority to do anything about it.

Cardinal Pell said the process of giving evidence had been a "hard slog" but it was designed to make things better for survivors and prevent further abuse.

"I hope that my appearance here has contributed a bit to healing, to improving the situation," he said.

In a statement after the full report was released, Cardinal Pell claimed the commissioners' views were not supported by evidence.

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Australian Associated Press