Tius is a Catholic titular see

Titular see

A titular see in various churches is an episcopal see of a former diocese that no longer functions, sometimes called a "dead diocese". The ordinary or hierarch of such a see may be styled a "titular bishop", "titular metropolitan", or "titular archbishop"....

. The original diocese was a suffragan of Claudiopolis

Bolu

- Places of interest :The countryside around Bolu offers excellent walking and other outdoor pursuits. There are hotels in the town for visitors. Sights near the town include:* The 14th century mosque, Ulu Camii...

 in Honorias

Honorias

Honorias was a late Roman province encompassing parts of Bithynia and Paphlagonia in Asia Minor . Its capital was Claudiopolis , and its governor was of the rank of praeses....

; its see was also known as Tium, Tieium, Tieion, Tios or Tion . It corresponds to modern Filyos (Hisarönü). Modern Filyos (Filyas) stands on the ruins of ancient Tium, which included remains of ramparts and sculptures. It is not far from the mouth on the Black Sea

Black Sea

The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...

 of the Filyas River, the Billaeus in the antique period.

According to Strabo

Strabo

Strabo, also written Strabon was a Greek historian, geographer and philosopher.-Life:Strabo was born to an affluent family from Amaseia in Pontus , a city which he said was situated the approximate equivalent of 75 km from the Black Sea...

 (542, 545) the town was only remarkable as the birthplace of Philetaerus

Philetaerus

Philetaerus was the founder of the Attalid dynasty of Pergamon in Anatolia.- Early life and career under Lysimachus :...

, founder of the royal dynasty of Pergamus

Pergamus

In Greek mythology, Pergamus was the son of the warrior Neoptolemus and Andromache.In the Bible, Pergamus was quoted as an Asian kingdom where an unknown being from the Book of Revelation sends a message to the seven churches of Asia...

. The coins give a certain Dionysius

Dionysius

The Graeco-Roman name Dionysius, deriving from the name of the Thracian god Dionysus, was exceedingly common, and many ancient people, famous and otherwise, bore it. It remains a common name today in the form Dennis . The modern Greek form of the name is Dionysios or Dionysis. The Spanish form of...

 as the founder; in fact it was the site of a temple of Dionysius and one of Jupiter

Jupiter (mythology)

In ancient Roman religion and myth, Jupiter or Jove is the king of the gods, and the god of the sky and thunder. He is the equivalent of Zeus in the Greek pantheon....

. Tieion was a Greek colony of Miletus

Miletus

Miletus was an ancient Greek city on the western coast of Anatolia , near the mouth of the Maeander River in ancient Caria...

Novel xxix of Justinian locates the town in Paphlagonia

Paphlagonia

Paphlagonia was an ancient area on the Black Sea coast of north central Anatolia, situated between Bithynia to the west and Pontus to the east, and separated from Phrygia by a prolongation to the east of the Bithynian Olympus...

 but geographically is in Bithynia

Bithynia

Bithynia was an ancient region, kingdom and Roman province in the northwest of Asia Minor, adjoining the Propontis, the Thracian Bosporus and the Euxine .-Description:...

. George Pachymeres

George Pachymeres

Georgius Pachymeres , a Byzantine Greek historian and miscellaneous writer, was born at Nicaea, in Bithynia, where his father had taken refuge after the capture of Constantinople by the Latins in 1204...

 (I, 312) mentions Tium among the Byzantine towns which escaped the attacks of the Seljuks in 1269.

Bishops

Le Quien (Oriens christianus, I, 575) mentions among its bishops:

• Apragmonius at the First Council of Ephesus in 431;
• Andrew in 518;
• Eugenius in 536;
• Longinus at the Sixth General Council in 681;
• Michael at the Seventh General Council in 787;
• Constantine, at the Eighth General Council in 869, and author of an account of the transfer of the relics of St. Euphemia of Chalcedon (Acta Sanctorum
  Acta Sanctorum
  Acta Sanctorum is an encyclopedic text in 68 folio volumes of documents examining the lives of Christian saints, in essence a critical hagiography, which is organised according to each saint's feast day. It begins with two January volumes, published in 1643, and ended with the Propylaeum to...
  
  , September, V, 274-83).

This see figures in all the Notitiae episcopatuum

Notitiae Episcopatuum

The Notitiae Episcopatuum are official documents that furnish Eastern countries the list and hierarchical rank of the metropolitan and suffragan bishoprics of a church....

.