Vatican leaks scandal: Five face trial in Holy See
Five people have gone on trial in the Vatican accused of leaking and publishing secret documents revealing mismanagement in the Holy See.
Two journalists who cited the documents in two books will face the tribunal, along with two members of a papal commission and an assistant.
If convicted, they could be jailed for up to eight years.
Media groups have condemned the trial. One of the journalists charged called it "an attack on press freedom".
The journalists, Emiliano Fittipaldi and Gianluigi Nuzzi, featured allegations of the misuse of charitable and other funds in their books Merchants in the Temple and Avarice.
The allegations included the lavish refurbishment of apartments for cardinals and others.
The three accused of leaking the documents are Spanish priest Msgr Angelo Lucio Vallejo Balda, his secretary and an Italian public relations expert who sat on a commission that advised the Pope on economic reform.
Risky trial - by Caroline Wyatt, BBC religious affairs correspondent, Rome
The danger of this trial for the Vatican is that it will make it look vengeful and draw even more attention to the allegations contained in the books.
One of the journalists has started tweeting the hashtag #NoInquisition, and has gained much sympathy from supporters of freedom of speech and the freedom of the press, including from the international security body, the OSCE. The journalists were attending the trial voluntarily - the Vatican has no legal powers to force them, unless it moves to extradite them from Italy.
The other question is what the Vatican hopes to achieve.
If the journalists were found guilty, and given a jail sentence, it would create a bizarre diplomatic situation. The Vatican has only four holding cells and no long-term prison.
It would also need to extradite the journalists from Italy for something that is not a crime in Italy, and then ask Italy to imprison them. Italian law protects press freedom, unlike the laws of the Holy See.
And with a "holy year of mercy" starting this December, the Vatican also risks looking rather less than merciful when its dirty laundry is aired in public.
Media groups have urged the Vatican to drop the charges.
Nina Ognianova, of the Committee to Protect Journalists, said: "Journalists should be allowed to carry out their role as watchdog and investigate alleged wrongdoing without fear of repercussions."
The journalists involved called the trial "Kafka-esque", saying neither they or their lawyers had seen details of the charges.
Mr Fittipaldi said: "This is a trial against freedom of the press. In no other part of the world, at least in the part of the world that considers itself democratic, is there a crime of a scoop, a crime of publishing news."
The rapidity with which the Vatican has moved to charge the five stands in sharp contrast to the length of time it has taken to help bring many priests accused of child sex abuse to trial, our correspondent says.
Apart from Msgr Vallejo Balda, Vatican authorities have also charged the Spanish priest's assistant Nicola Maio, and PR expert Francesca Chaouqui.
The special reform commission they were serving was set up by Pope Francis to tackle the Vatican's financial holdings and propose reforms to improve cash flow to the poor.