They had repeatedly called on Rome to dismiss Roger Vangheluwe (87) from the clergy - the church's maximum penalty following the abuse of minors.
As the Catholic weekly "The Tablet" reports, Belgium's Justice Minister Paul Van Togchelt offered to present the Vatican with pornographic images from Vangheluwe's computer that investigators had found there.
Vangheluwe, Bishop of Bruges from 1984 until his resignation in 2010, had admitted to abusing two nephews in the 1980s.
The scandal also damaged the reputation of Cardinal Godfried Danneels (1933-2019), who is said to have covered up Vangheluwe's offences. Danneels was considered a patron of the current Pope Francis.
Since his resignation under pressure from the Church, Vangheluwe has lived in seclusion in a monastery and is no longer allowed to enter his home diocese.
Nevertheless, he remains a retired bishop and is still allowed to celebrate mass in private.
Vangheluwe wrote to Rome - content unknown
His successor, Jozef De Kesel, campaigned for Vangheluwe to be dismissed from the clergy.
According to "The Tablet", Bishop Johan Bonny of Antwerp announced in September that Belgium's bishops had asked the 87-year-old Vangheluwe to resign from the clergy and had also asked the Vatican to take this step.
It had become known shortly beforehand that Vangheluwe had written to Rome; however, he refused to disclose the contents of the letter.
The Pope's ambassador to Belgium, Archbishop Franco Coppola, said that he assumed that Vangheluwe had not asked to be dismissed from the clergy in the letter.
According to the Belga news agency, Nuncio Coppola said that the corresponding request would normally have been approved and published within two months.
Coppola was only received by Pope Francis on Saturday.
The content of the conversation was not disclosed, but observers assumed that the meeting was about the Vangheluwe affair.
According to secular criminal law, the offences of which he is accused are time-barred.
According to ecclesiastical criminal law, the statute of limitations can be suspended for serious offences.
Before his trip to Rome, Coppola had publicly stated that he was "convinced that Vangheluwe cannot remain a bishop".
The affair threatens to overshadow Pope Francis' planned visit to Belgium to mark the 600th anniversary of the Catholic University of Leuven/Louvain.
The Vatican had confirmed the trip at the end of January.