What Caligula argued from the facts, Plato, in the dialogue called the Politicus , argued in defining the civil or kingly man, on the basis of right. But if great princes are rare, how much more so are great legislators? The former have only to follow the pattern which the latter have to lay down. The legislator is the engineer who invents the machine, the prince merely the mechanic who sets it up and makes it go. “At the birth of societies,” says Montesquieu, “the rulers of Republics establish institutions, and afterwards the institutions mould the rulers.” 13