The pope's butler's theft and leaking of confidential documents harmed the pontiff and the entire Catholic church, the Vatican court which convicted him has declared.
The three-judge tribunal issued its written explanation of how it reached its October 6 ruling against Paolo Gabriele, who was convicted of aggravated theft and sentenced to 18 months, currently being served under house arrest.
Gabriele confessed to photocopying papal documents and giving them to an Italian journalist, saying the pope was not being informed of the "evil and corruption" around him and that he believed exposing the problems publicly would put the church back on the right track.
The revelations of petty bureaucratic infighting, intrigue and allegations of corruption and homosexual liaisons marked the biggest Vatican security breach in modern times.
Noting what they called Gabriele's "simplistic" intellectual capacity, the judges acknowledged that he thought he was doing the right thing by leaking the documents. But they said his theft damaged the pope himself and the rights of the Holy See, the Vatican City state and the entire Catholic Church.
"In particular, Gabriele's actions violated not just the fundamental right to a good name and reserve owed all involved, but also the secrecy of actions owed to a sovereign," the judges wrote.
The Vatican spokesman, the Rev. Federico Lombardi, said prosecutors have a few more days to decide whether or not to appeal against the sentence. Gabriele's lawyer has already decided not to appeal.
Once the deadline passes, Gabriele will begin serving his sentence. Previously the Vatican had said he would serve it in an Italian prison, given the Vatican does not have a long-term detention facility. But Rev. Lombardi said he would now serve it in the Vatican, where he spent the first two months of detention after his May 23 arrest. Rev. Lombardi repeated that the pope could still pardon Gabriele.
Gianluigi Nuzzi's book, "His Holiness: Pope Benedict XVI's Secret Papers" convulsed the Vatican for months and prompted an unprecedented response, with the pope naming a commission of cardinals to investigate the origin of the leaks alongside Vatican magistrates.
A co-defendant, Claudio Sciarpelletti, a computer expert in the Vatican secretariat of state, was accused of aiding and abetting Gabriele's crime. His trial is due to start on November 5.