Is conferred on a prelate by way of title only, no concomitant jurisdiction being given in the respective diocese. In the early centuries of the Church, and in some cases well into the Middle Ages, these dioceses were flourishing residential sees; but later, ravaged by schism, persecution, and invasion, they had to be abandoned and became known as dioceses in partibus infidelium. In order to conserve the memory of these ancient sees the practice was begun, at the time of the Fifth Lateran Council (1512–17), in the pontificate of Leo X, of conferring them titularly on cardinals of the Roman Curia who would request the privilege. Later the custom evolved, as it exists today, of conferring these titles on certain bishops who are not diocesan bishops (e.g., auxiliary bishops and bishops attached to the Roman Curia). In the latter part of the 19th century, being informed that the designation in partibus infidelium had become offensive to the governments of some of the lands in which these sees were located, the Holy See, by a decree of 1882, changed it to "titular sees." The Annuario Pontificio of 2000 lists more than 1,500 such sees, located principally in ancient Asia Minor, Palestine, Syria, and Africa.
Bibliography: f. claeys-bouuaert, Dictionnaire de droit canonique, ed. r. naz, 7 v. (Paris 1935–65) 5:574–575. Annuario Pontificio (Rome 1912–) (1964) 501–707, 1553–54.
"Titular See." New Catholic Encyclopedia. . Encyclopedia.com. (November 17, 2018). https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/titular-see
"Titular See." New Catholic Encyclopedia. . Retrieved November 17, 2018 from Encyclopedia.com: https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/titular-see