CESARIO of Saint Bonaventure. - Carmelite missionary, born Giovanni, son of the distinguished orientalist Pietro Bertius. Born on 16 March 1615 in Leiden (Holland) to Protestant parents, died on 27 October 1662. Having converted to Catholicism, he entered the Discalced Carmelite Order in Paris on 18 July 1632 and was initiated into Carmelite missions in Holland, where he founded (1648) a station in The Hague. After bringing many heretics and apostates back to the Catholic faith, he was recalled (1657) to Paris. He was then appointed prior of the convent in Malta, where he died.
In addition to various reports on the mission in Holland, still in manuscript form, he published: 1) *Tractatus de S. mo Eucharistiae Sacramento* against Protestants; 2) *Breve compendium doctrinae christianae* (Brussels 1650).