Chronology of Catholic Dioceses:Note on the Diocese of Alger / Iulia Caesarea - 1838
When the Diocese of Alger was established in 1838, it was also named Iulia Caesarea, after a Diocese which was believed to have been on that same location in the first Christian centuries. That presumption seems, however, to have been mistaken. It is more probable that Alger is on the same spot as the pre-islamic diocese of Icosium. The name Iulia Caesarea is still retained, but it is now (Annuario Pontificio 2000) as an "added title", and not as the old, alternative name of the (Arch)diocese.