CANBERRA, Australia (AP) — The most senior Catholic to be convicted of child sex abuse took his appeal to Australia’s highest court Wednesday in potentially his last bid to clear his name.

Cardinal George Pell was sentenced a year ago to six years in prison for molesting two 13-year-old choirboys in Melbourne’s St. Patrick’s Cathedral while he was the city’s archbishop in the late 1990s.

He was convicted by the unanimous verdict of a Victoria state County Court jury in December 2018 after a jury in an earlier trial was deadlocked.

A Victoria Court of Appeal rejected his appeal against his convictions in a 2-1 majority decision in August last year.

Pope Francis’ 78-year-old former finance minister is arguing before the High Court that the guilty verdicts were unreasonable and could not be supported by the whole of the evidence from more than 20 prosecution witnesses who include priests, altar servers and former choirboys.

Seven judges are hearing the case over two days.

Pell's lawyer Bret Walker told the judges that there had been a “reversal of onus” in which Pell was expected to prove the offending didn't happen instead of prosecutors proving the crimes were committed beyond reasonable doubt.

“That is a wrong question which sends the inquiry onto a terribly damaging wrong route,” Walker said.

Walker said the allegations that Pell had molested the two boys in a priests' sacristy moments after a Mass could not be proved if the jury had accepted the evidence of sacristan Maxwell Potter and Monsignor Charles Portelli.

Potter had testified that the sacristy was kept locked during Masses and Portelli had given evidence that he was always with Pell while he was dressed in his archbishop's robes.

Prosecutors have told the judges in written submissions that it is not their role to determine whether it was open to the jury to find the offending behavior proven beyond reasonable doubt.

Outside court, Pell supporters clashed with a man from a victims advocacy group. Michael Advocate from Victim Justice held signs saying, “Burn in hell Pell.”

A group of Pell supporters tried to block Advocate from speaking to reporters, yelling for Pell to be forgiven.

The group of about 50 supporters, many holding Australian flags, sang hymns outside of the court as lawyers prepared for the case inside.

The court will effectively hear Pell’s appeal in its entirety before they technically decide whether they will even hear his appeal.

They could decide he does not have permission to appeal, he has permission to appeal but the appeal is denied, or he has permission to appeal and the appeal is upheld.

The judges could also send Pell’s appeal back to the Victoria Court of Appeals to be reheard by another three judges.

Pell had been working as a gardener at a Melbourne prison. But he was transferred in January after a drone illegally flew overhead in a suspected attempt to photograph the famous inmate, the Herald Sun newspaper reported.

He was moved to the maximum-security Barwon Prison near Geelong, southwest of Melbourne.

He hasn't travelled to Canberra for his appeal hearing. It is not known when the judges will deliver their rulings.

One of Pell’s victims died of a heroin overdoses in 2014 without telling anyone of the abuse.

The survivor went to police after attending his friend’s funeral. Neither victim can be identified because the identities of sexual assault victims must be kept secret under state law.