One morning the soldier who had been on sentry duty the night before asked to see his centurion. "Last night I dreamed that hordes of barbarians would sweep down from the north and attack our fort tonight," he reported. The centurion wasn't quite sure that he believed in prophetic dreams, but decided to double the patrols just in case. That night, the barbarians made their attack, but thanks to the extra patrols they were easily defeated. After the battle, the centurion thanked the soldier for his warning and then confined him to barracks until the Ides of March as a punishment. Why?