Born at Castronuovo (today Castronuovo di Sant'Andrea), a small town in the province of Potenza, in Basilicata, his baptismal name was Lancelotto, which he changed to Andrew when he entered the Order of Theatines. After receiving his elementary training in the school at Castronuovo, he was sent to Venice to pursue a course in the humanities and in philosophy. Being a handsome youth, his chastity was often exposed to danger from female admirers, and to escape their importuning he took ecclesiastical tonsure.