The numbers are not ascertained by any ancient writer or original catalogue; for the partial lists of the eastern churches are comparatively modern. The patient diligence of Charles a Sto. Paolo, of Luke Holstenius, and of Bingham, has laboriousls investigated all the episcopal sees of the Catholic church, which was almost commensurate with the Roman empire. The ninth book of the Christian Antiquities is a very accurate map of ecclesiastical geography.