A recent theory conjectures that he was actually born as Ivan Hrobat, the illegitimate son of Katarina Hrobat and a nobleman of the Lanthieri family, and that the surname Lionelli was purchased to avoid embarrassment.
[7][8] He took the name "Joannes Baptista à Sancta Cruce Vippacensi" upon joining the Order of Friars Minor Capuchin in reference to his native town and probably also to the Spanish mystic St. John of the Cross.
Lionelli wrote over 230 sermons, which he published in a series of five books entitled Sacrum promptuarium (The Holy Handbook).
[9] One of his best-known sermons is Na noviga lejta dan (On New Year's Day).
The syntax presents a typical Baroque style, with references to Classical tradition.