The most senior Catholic to be found guilty of child abuse is launching an appeal against his conviction.
Australian Cardinal George Pell appeared in court wearing a cleric's collar for the hearing, set to be heard by judges on Wednesday and Thursday.
Pell has been held in prison since he was sentenced in March to six years for molesting two choir boys in a Melbourne cathedral more than 20 years ago.
The 77-year-old has been held in a special protective custody as paedophiles are deemed to be at risk of harm from other prisoners.
Pell, who was Pope Francis' former finance minister, was unanimously convicted of orally raping a 13-year-old boy and indecently dealing with another boy in the late 1990s.
Pell had become archbishop of Melbourne, Australia's second city, just months before.
Pell’s lawyer, Bret Walker, told Justices Anne Ferguson, Chris Maxwell and Mark Weinberg the main ground for appeal was that the jury could not have found Pell guilty beyond reasonable doubt on the evidence.
In written submissions, Pell’s lawyers argued that more than 20 prosecution witnesses who had an official role in the Sunday Mass in 1996, after which the then-Archbishop Pell molested the boys in a rear room over five or six minutes, gave evidence that the offences did not or could not have occurred.
“This evidence constituted a catalogue of at least 13 solid obstacles in the path of a conviction,” the submissions said.
“No matter what view was taken of the complainant as a witness, it was simply not open to a jury to accept his words beyond reasonable doubt,” they added.
One of Pell’s victims died of a heroin overdose in 2014 at the age of 31, apparently without making any accusation of abuse.
If the appeal judges rule that the verdict is unsafe on the evidence, Pell would by acquitted and would not have to be retried.
Pell’s lawyers have also said they will argue that the trial judge erred in not allowing them to use a video graphic in their closing address.
They said the graphic would demonstrate that the crimes that were alleged would have been impossible.
A third ground details an alleged “fundamental irregularity” in the trial in that Pell was not arraigned — asked if he pleaded guilty or not guilty — in front of the chosen jury.
A victory on either of those grounds could result in Pell being retried, but he would likely be freed on bail until then.