Father Gabriele Martinelli, now 29, was accused of having forced a person known only as LG to have sex, mostly while they were both minors.

Martinelli, for whom the prosecution had sought a six-year custodial sentence, was not a priest at the time.

The prosecution had sought a four-year sentence for Father Enrico Radice, 72, who was rector at the time and was charged with having covered up the alleged abuse.

Both Martinelli and Radice had consistently denied wrongdoing and accused LG of mounting a personal vendetta against them.

The alleged abuse took place in the Pius X Pre-Seminary, which houses altar boys who serve Mass in St Peter’s, including for popes, and are thinking of becoming priests.

Some of the charges were affected by the statue of limitations, and details of the court ruling were due to be published later on Wednesday.