Among the Romans, the word exilium properly signified an interdiction or exclusion from water and fire; the necessary consequence of which was, that the interdicted person had to betake himself to some other country, as there was no living without fire and water in his own. Thus Cicero observes, that the form of the sentence did not express exilium, but only aquae et ignis interdictio; and he also remarks that exile was not properly a punishment, but a voluntarily flying from or avoiding the punishment decreed: Exilium non esse supplicium, sed perfugium portusque supellicii. He adds that there was no crime among the Romans, as among other nations, punished with exile; but exile was a resource of which people voluntarily availed themselves, in order to avoid chains, ignominy, famine, or death.

The Athenians frequently sent their generals and great men into exile, out of envy of their merits, or distrust of their authority and influence in the state.