For Aristotle, this alternation between command and obedience even constituted the virtue or excellence of the citizen. "It would appear," he wrote, "that the excellence of a good citizen is to be capable of commanding well and obeying well [to dynasthai kai archein kai archesthai kalos]."And this dual capacity, so essential to the citizen, was learned through alternating the roles: "It is said, and quite rightly, that no one can command well who has not obeyed well [ouch estin eu arxai me archthenta].// The phrase used by Aristotle was proverbial. Its origin was attributed to Solon, which gives some indication of its importance in the political culture of Athens. The expression "to command well" should here be understood in its fundamental sense: to exercise the activity of command in conformity with its essence and perfection. Generally speaking, a task may legitimately be entrusted to someone capable of performing it to perfection. Rotation in office thus provided the basic legitimation of command. What gave a right to rule was the fact of having once been in the opposite position.