According to Greek mythology, Olbe had been built by Ajax, the son of Teucer; it contained a temple of Zeus, whose priest once ruled over all Cilicia Aspera.
Strabo described it:
"Above this [Kyinda] and Soloi [in Kilikia] is a mountainous country, in which is a city Olbe, with a temple of Zeus, founded by Aias the son of Teukros. The priest of this temple became dynast of Kilikia Trakheia; and then the country was beset by numerous tyrants, and the gangs of pirates were organized. And after the overthrow of these they called this country the domain of Teukros, and called the same also the priesthood of Teukros; and most of the priests were named Teukros or Aias."
Its ruins, north of Silifke in the Turkish province of Mersin, are called Oura in Turkish.
Olba was a suffragan of the Metropolitan of Isauria's provincial capital Seleucia, but faded like most sees in Asia Minor. Olba maintained a sizable Christian population in the 4th and 5th centuries, when the Temple of Zeus was converted into a church.
Le Quien (Oriens christianus, II, 1031) gives four bishops between the fourth and seventh centuries; but the Notitiæ episcopatuum mentions the see until the thirteenth century.
The diocese was nominally restored as titular bishopric of the episcopal (lowest) rank under the name Olba (Latin and Curiate Italian); Latin adjective Olbiensis.
In 1927 it was suppressed, having had the following incumbents, all of the fitting Episcopal (lowest) rank:
Louis-François-Alexandre de Jarente de Senas d’Orgeval (1780.12.11 – 1788.05.28), Coadjutor Bishop of Orleans (France) (1780.12.11 – 1788.05.28), succeeding as Bishop of Orléans (1788.05.28 – retired 1801.10.29); died 1805
Bernard Hermann Koeckemann, Picpus Fathers (SS.CC.) (1881.05.17 – 1892.02.22) as Coadjutor Apostolic VicarHawaiian Islands (Polynesia, USA; now Diocese of Honolulu) (1881.05.17 – 1882.06.11), succeeding as Vicar Apostolic of Hawaiian Islands (USA) (1882.06.11 – death 1892.02.22)
Charles-François Lasne, Lazarists (C.M.) (1911.02.15 – death 1927.06.23) as Coadjutor Vicar Apostolic of Fort-Dauphin (Madagascar) (1911.02.15 – 1927.06.23)
In 1933 it was again restored as titular bishopric of Olba. It is vacant since decades, having had the following incumbents, so far of the fitting episcopal rank :
^Edwards, Robert W., "Diocaesarea and Olba" (2016). The Eerdmans Encyclopedia of Early Christian Art and Archaeology, ed., Paul Corby Finney. Grand Rapids, Michigan: William B. Eerdmans Publishing. pp. 421–422. ISBN978-0-8028-9016-0.