The effectiveness of these various arrangements for the provisioning of troops upon a march was such that Persian armies were rarely, if ever, in any difficulty with respect to their subsistence. Once only in the entire course of their history do we hear of the Persian forces suffering to any considerable extent from a want of supplies. According to Herodotus, Cambyses, when he invaded Ethiopia, neglected the ordinary precautions and brought his army into such straits that his men began to eat each other. This caused the total failure of his expedition, and the loss of a great proportion of the troops employed in it. There is, however, reason to suspect that, even in this case, the loss and difficulty which occurred have been much exaggerated. The Persians readily gave quarter to the enemy who asked it, and generally treated their prisoners of war with much kindness. Personages of importance, as monarchs or princes, either preserved their titles and their liberty, with even a certain nominal authority, or received appanages in other parts of the Persian territory, or, finally, were retained about the Court as friends and table-companions of the Great King. Those of less rank were commonly given lands and houses in some province remote from their own country, and thenceforth held the same position as the great mass of the subject races. Exchanges of prisoners do not seem to have been thought of. In a few cases, persons, whom we should regard as prisoners of war, experienced some severities, but probably only when they were viewed by the Persians, not as fair enemies, but as rebels. Rebels were, of course, liable to any punishment which the king might think it right to inflict upon them, and there were occasions after a revolt when sentences of extreme rigor were passed upon the persons considered to have been most in fault. 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.