VATICAN CITY – The pope’s once-trusted butler went on trial Saturday for allegedly stealing papal documents and passing them off to a journalist in the worst security breach of the Vatican’s recent history – a case that embarrassed the Vatican and may shed further light on the discreet, internal workings of the papal household.

In its first hearing in the case, the three-judge Vatican tribunal threw out some evidence gathered during the investigation of butler Paolo Gabriele, who is charged with aggravated theft. It also decided to separate Gabriele’s trial from that of his co-defendant, a computer expert charged with aiding and abetting the crime.

Gabriele is accused of taking the pope’s correspondences, photocopying the documents and handing them to Italian journalist Gianluigi Nuzzi, whose book “His Holiness: The secret papers of Pope Benedict XVI,” was published to great fanfare in May.