Roman Province

In Ancient Rome, a province (Latin: provincia, pl. provinciae) was the basic, and, until the Tetrarchy (293 AD), largest territorial and administrative unit of the empire's territorial possessions outside of Italy. The word province in modern English has its origins in the term used by the Romans.

Provinces were generally governed by politicians of senatorial rank, usually former consuls or former praetors. A later exception was the province of Egypt, incorporated by Augustus after the death of Cleopatra: it was ruled by a governor of equestrian rank only, perhaps as a discouragement to senatorial ambition. This exception was unique, but not contrary to Roman law, as Egypt was considered Augustus' personal property, following the tradition of earlier, Hellenistic kings.

The Latin word provincia originally meant any task or set of responsibilities assigned by the Senate to an individual who held imperium ("right of command"), which was often a military command within a specified theater of operations. Under the Roman Republic, the magistrates were elected to office for a period of one year, and those serving outside the city of Rome, such as consuls acting as generals on a military campaign, were assigned a particular provincia, the scope of authority within which they exercised their command.

The territory of a people who were defeated in war might be brought under various forms of treaty, in some cases entailing complete subjection (deditio). The formal annexation of a territory created a "province" in the modern sense of an administrative unit geographically defined. Republican provinces were administered in one-year terms by the consuls and praetors who had held office the previous year and who were invested with imperium.

...
Wikipedia