The author of the book of Vatican secrets that earned the pope's ex-butler an 18-month sentence for stealing private correspondence is appealing for clemency and trying to explain his source's motives.

Several European newspapers published an op-ed piece by Gianluigi Nuzzi on Monday in which the Italian journalist defended the actions of Paolo Gabriele and sought to put them in a context he said hadn't been fully explained during Gabriele's trial. Nuzzi provided an advance copy to The Associated Press.

A Vatican tribunal on Saturday convicted Gabriele of aggravated theft for stealing the pope's correspondence and passing it onto Nuzzi. Gabriele is under house arrest in his Vatican City apartment awaiting an expected papal pardon.

Nuzzi notes Gabriele's leaks didn't reveal state secrets but merely shed light on events that were damaging the church.