Camillus Mazella was born in Benevento, Italy, in 1833. At the age of 24 he became a member of the Society of Jesus and about ten years later was sent to the United States, where he taught dogmatic theology in Georgetown College (now University). In 1867 he was naturalized as an American citizen. Pope Leo XIII was very interested in his theological writings and because of this he was summoned to Rome in 1878 by Fr General Beckx, and made professor of dogmatic theology in the Roman college.
In 1885 , the pope appointed him consulter to the Congregation of the Inquisition and a year later, on this day, he created him cardinal. The rest of his life is spent in direct service of the Holy See. His first period of work was for the Propaganda Fide , where he deals with matters relating to the Eastern rites and where he chaired the committee that examines the status of new religious institutes.Then he became prefect of the Congregation of the Index and in 1893 , prefect of the Congregation oversee ecclesiastical studies.
Perhaps his strongest legacy was his involvement as an advisor in the process that led to the Papal Bull Apostolicae Curae issued in 1896 by Pope Leo XIII, declaring all Anglican ordinations to be "absolutely null and utterly void". This was because of the deficiency of intention and of form of the Anglican ordination rites. According to the Pope the rites indicated priesthood to be an appointment or blessing, instead of a sacramental conferral of actual grace by the action itself. The validity of Anglican Orders had become a life question with the flourishing of the Oxford Movement inspired by Cardinal Newman. Many Anglican ministers wishing to be received into the Catholic Church were being ordained unconditionally, as repeating ordinations was theologically impossible, by ordaining them unconditionally it was implicitly suggesting that there original orders were invalid. The Bull was therefore making explicit was had been implicit. Many Anglican theologians pointed out that this was inconsistent with the Catholic view that some of the Eastern Rite Liturgies were valid, even though, in their eyes they suffered from the same defect.