Pell said his time in prison was somewhat like a retreat – removed from the world and isolated from social interaction.
While there were moments where he wondered why God was allowing his suffering, he also hopes that his ordeal can bring souls to Christianity.
Pell said he is not angry looking back at his experience, but is glad to be back in Rome to thank Pope Francis for his support.
Although he is no longer prefect of the Secretariat for the Economy, as his term expired last year, he said his successor, Jesuit priest Fr. Juan Antonio Guerrero Alves is "a good man, a competent man."
"He's headed in the right direction and I totally support him," Pell said. "I just hope he's not thwarted the way I am. The Holy Father says there's got to be an investment committee set up to manage Vatican investment. We recommended that 5 years ago. Now that's got to be men and women by honest and really professional investors and given effective control. That's what my successor wants and I fully support that so that we can get away from this shadowy world that the Vatican has dealt with, not all always, but so many times, for decades."
Reflecting on his own time heading the secretariat, Pell said he "didn't quite realize just the level of sophistication, corruption, and a good measure of incompetence that would be there."
During his time as prefect, he discovered more than 1 billion euro in accounts that had not been declared.
Pell addressed speculations that the sex abuse allegations against him were an attempt to prevent his anti-corruption work in Vatican finances. He said that while there is evidence to support this idea, there is not proof, and more investigation is needed.
"A lot of the people who were working for serious reform here believed there was a connection. Amongst my supporters in Australia, almost nobody believed that there was a connection," he continued. "We now know that quite a number of the criminal elements around the place hoped that I would come to grief in Australia, whether they knew more than that we don't know."
Some of this speculation involves media reports that Cardinal Angelo Becciu sent 700,000 euros of Vatican funds to Australia during Pell's sexual abuse trial, possibly as a payment for Pell's accusers.
In September, Becciu resigned as prefect of the Vatican's Congregation for the Causes of Saints and from the rights extended to members of the College of Cardinals.
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He worked previously as the number two-ranking official in the Vatican's Secretariat of State, and has been connected to an ongoing investigation of financial malfeasance at the secretariat. He had clashed with Pell over reform efforts in the Vatican.
CNA has reported that in 2015 Becciu seemed to have made an attempt to disguise the loans on Vatican balance sheets by canceling them out against the value of the property purchased in London. Senior officials at the Prefecture for the Economy said that when Pell began to demand details of the loans, Becciu called the cardinal in to the Secretariat of State for a "reprimand."
In 2016, Becciu also canceled a planned external audit of all Vatican departments.
Asked about Becciu's resignation, Pell said, "I hope the cleaning of the stables in both my state of Victoria and the Vatican continues." He added that "Becciu has a right to a trial. Like everybody else, he has a right to due process. So let's just see where we'll go."
Overall, Pell said he thinks the Church is doing a good job of helping sex abuse victims. He pointed to protocols aimed at prevention, reporting and investigation claims, and offering compensation and counseling to survivors.
"I think, for a long time, the Church has basically been heading in the right direction and this hasn't been as sufficiently recognized," he said.