The territorial concept evolved gradually from military commands into defined administrative regions during the middle republic. Direct Roman administration arrived only after the Fourth Macedonian War in 148 BC when Macedonia became a permanent province.
Sicily became the first permanent province created after the First Punic War ended in 241 BC. Appian reported that sending a praetor to Sicily became normal by 241 BC while Solinus indicated 227 BC instead.
The lex Calpurnia de repetundis passed in 149 BC established a permanent court to try corruption cases. This legislation reacted against profiteering by praetorian governors who lacked oversight and threatened Roman control.
These provinces contained 22 of the 28 extant Roman legions representing over 80 per cent of military forces. The provinces assigned to Augustus became known as imperial provinces while remaining areas became public or senatorial provinces.
In the 290s Diocletian divided the empire anew into almost a hundred provinces including Roman Italy itself. These provinces grouped into originally twelve dioceses headed usually by a vicarius who oversaw their affairs.
Sicily taken over from Carthaginians was annexed at end of First Punic War in 241 BC. Sardinia and Corsica taken over from Carthaginians were annexed soon after Mercenary War in 237 BC and 238 BC respectively. Hispania Citerior along east coast Iberian Peninsula part of territories taken from Carthaginians in 197 BC.