Short answers, pulled from the story.
Roman provinces were administrative regions of ancient Rome outside Roman Italy, controlled first under the Roman Republic and later the Roman Empire. Each province was ruled by a Roman-appointed governor, who in the Republic was typically a former consul or praetor, and in the imperial period served as either a senatorial proconsul or an imperial legate with the title legatus Augusti pro praetore.
Sicily was the first permanent Roman province, created after the First Punic War. The sources disagree on the precise date that a praetor was regularly dispatched there: Appian reports 241 BC and Solinus gives 227 BC.
The Latin word provincia originally referred to a task or responsibility assigned to a Roman magistrate, not a geographic territory. Writers such as Plautus, Terence, and Cicero used it to describe something like a ministerial portfolio; for example, the treasury was the provincia of a quaestor.
In 27 BC, Augustus retained command of Spain, Gaul, Syria, Cilicia, Cyprus, and Egypt, which held 22 of the 28 Roman legions in existence; these became known as imperial provinces. The remaining provinces, mostly demilitarized, became senatorial or public provinces, still assigned annually by the senate.
Diocletian, during the tetrarchy of AD 284-305, divided the empire into almost a hundred provinces including Roman Italy, which had previously been exempt. These provinces were grouped into originally twelve dioceses, each overseen by a vicarius, creating a three-level hierarchy of prefectures, dioceses, and provinces.
In 123 or 122 BC, the tribune Gaius Sempronius Gracchus passed the lex Sempronia de provinciis consularibus, which required the senate to designate consular provinces before consular elections and made that designation immune from tribunician veto. Between 122 and 53 BC, the share of consular provinciae that were permanent provinces rose from 22 per cent to 60 per cent as a result.