At the same time, there is much it left unchanged in Australia.

Importantly, it remains vital that the community listens to survivors of sexual abuse in the church, and that it supports those who come forward.

Second, the national discussion of the Catholic church's handling of paedophilia in the clergy continues, and must continue.

Not long after the court decision arrived, leaders in the Catholic church began discussing the meaning of Cardinal Pell's trial.

Archbishop of Sydney Anthony Fisher said that this had not only been a trial of Cardinal Pell, but also the nation's legal system and culture, adding that the High Court decision invited reflection on Australia's commitment to the presumption of innocence.

Archbishop of Melbourne Peter Comensoli said the only matter of the case was whether Cardinal Pell had committed "certain despicable crimes", and not the broader question of how church authorities had dealt with sexual abuse by a Catholic priest.

In a statement, Cardinal Pell himself said his trial was not a referendum on the Catholic church, nor on how church authorities in Australia dealt with paedophilia in the church.

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

It is true that the trial of Cardinal Pell in 2018 focused on whether he was guilty or not guilty of child sexual abuse, and the High Court's finding was that the jury ought to have entertained a reasonable doubt as to his guilt.

At the same time, the trial had other influences on Australians, shaping the way they thought about the church, while raising questions about its hierarchy for Catholics and non-Catholics.

Cardinal Pell's conviction in 2018 raised this question for both groups: how could a paedophile rise to the most senior ranks of the church, and what did this indicate about its handling of sexual abuse?

Catholics and non-Catholics will process how the High Court's decision changes their views of the church in coming weeks and months.

Catholics will also consider what standing Cardinal Pell has in their community, now his convictions have been overturned.

This is symbolised by a statement on Tuesday from St Patrick's College in Ballarat, which previously removed Cardinal Pell's name from a building.

It said it would wait for the full findings of the Royal Commission into Institutional Responses to Child Sexual Abuse to determine what, if any, steps to take with respect to those naming honours.

Questions remain too for the Vatican, shaken in 2018 by the conviction of Cardinal Pell. Like St Patrick's College, it will have to decide what place he holds in its institution.

More broadly, the legacy of the church's handling of child sex abuse remains in Australia and overseas, and requires apology, reparation and deep reform.

The trial in 2018, and even the High Court case, do reflect something about both the church and legal system in Australia. The nation's most senior Catholic faced a jury, in a secular court, away from the Vatican. His convictions were reviewed and quashed by the nation's highest court.

People will have their own views about this outcome, but it shows the Catholic church is subject to the judicial system in Australia. For people seeking justice in the future, that is something to take hope from.