John de Leoncello

John submitted to the Pope's order, and after spending several years in the Léoncel abbey, he left the Cisterians and joined the Benedictine Abbey of Île Barbe, with the agreement from his superior and subsequent approval from the Pope.

[2] After Madius' resignation, Pope Clement VI lifted John's suspension and appointed him as his successor as the bishop of Duvno on 20 July 1345.

[2] On 22 December 1345, he was exempted from paying a nomination fee due to poverty.

As other documents are lacking, it is unclear whether John took over the diocese or he was only a titular bishop.

The document on his exemption from paying the fee speaks of the poor conditions of the Diocese of Duvno after its patrons from the Šubić family lost political influence.