Bithynia et Pontus was the name of a province

Roman province

In Ancient Rome, a province was the basic, and, until the Tetrarchy , largest territorial and administrative unit of the empire's territorial possessions outside of Italy...

 of the Roman empire

Roman Empire

The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

 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...

 coast of Anatolia

Anatolia

Anatolia is a geographic and historical term denoting the westernmost protrusion of Asia, comprising the majority of the Republic of Turkey...

 (Turkey). It was formed by the amalgamation of the former kingdoms of 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:...

 (annexed by Rome 74 BC) and Pontus

Pontus

Pontus or Pontos is a historical Greek designation for a region on the southern coast of the Black Sea, located in modern-day northeastern Turkey. The name was applied to the coastal region in antiquity by the Greeks who colonized the area, and derived from the Greek name of the Black Sea: Πόντος...

 (annexed 64 BC).

The Roman writer Pliny the Younger

Pliny the Younger

Gaius Plinius Caecilius Secundus, born Gaius Caecilius or Gaius Caecilius Cilo , better known as Pliny the Younger, was a lawyer, author, and magistrate of Ancient Rome. Pliny's uncle, Pliny the Elder, helped raise and educate him...

 was governor of the province in 110-3 AD. His Epistulae

Epistulae (Pliny)

The Epistulae are a series of personal missives by Pliny the Younger directed to his friends and associates. These letters are a unique testimony of Roman administrative history and everyday life in the 1st century. The style is very different from that in the Panegyricus, and some commentators...

("Letters") to emperor Trajan

Trajan

Trajan , was Roman Emperor from 98 to 117 AD. Born into a non-patrician family in the province of Hispania Baetica, in Spain Trajan rose to prominence during the reign of emperor Domitian. Serving as a legatus legionis in Hispania Tarraconensis, in Spain, in 89 Trajan supported the emperor against...

 (ruled 98-117) are a major source on Roman provincial administration.

Under the administrative reforms of emperor Diocletian

Diocletian

Diocletian |latinized]] upon his accession to Diocletian . c. 22 December 244  – 3 December 311), was a Roman Emperor from 284 to 305....

, Bithynia et Pontus was divided into 3 smaller provinces, Bithynia, Honorias and Paphlagonia. These belonged to the diocese

Roman diocese

A Roman or civil diocese was one of the administrative divisions of the later Roman Empire, starting with the Tetrarchy. It formed the intermediate level of government, grouping several provinces and being in turn subordinated to a praetorian prefecture....

 of Pontica

Diocese of Pontus

The Diocese of Pontus was a diocese of the later Roman Empire, incorporating the provinces of northern and northeastern Asia Minor up to the border with the Sassanid Empire in Armenia. The diocese was established after the reforms of Diocletian, and its vicarius, headquartered at Amaseia, was...

, in turn part of the Prefecture of the East.