According to Herodotus, three thousand Babylonians were crucified by order of Darius, to punish their revolt from him; and, though this is probably an exaggeration, it is certain that sometimes, where an example was thought to be required, the Persians put to death, not only the leader of a rebellion, but a number of his chief adherents.

Crucifixion, or, at any rate, impalement of some sort, was in such cases the ordinary punishment.

Sometimes, before a rebel was executed, he was kept for a while chained at the king's door, in order that there might be no doubt of his capture.
Among the minor punishments of rebellion were branding, and removal of the rebels _en masse_ from their own country, to some remote locality.
In this latter case, they were merely treated in the same way as ordinary prisoners of war.

In the former, they probably became royal slaves attached to the household of the monarch.
Though the Persians were not themselves a nautical people, they were quite aware of the great importance of a navy, and spared no pains to provide themselves with an efficient one.

The conquests of Phoenicia, Cyprus, Egypt, and the Greek islands were undertaken, it is probable, mainly with this object; and these parts of the Empire were always valued chiefly as possessing skilled seamen, vessels, and dockyards, from which the Great King could draw an almost inexhaustible supply of war-ships and transports.