There had been, previously to this period, two praetors in Rome, the _Praetor Urbanus_, who adjudged cases between citizens in accordance with civil law, and the _Praetor Peregrinus_, who presided whenever a foreigner or alien was concerned, and judged according to the principles of natural law. Afterwards six praetors were appointed; and in the time of Antonius they judged not only civil but criminal cases, except those concerning the life of a citizen or the welfare of the state, which the people reserved for themselves. It must be remembered that the supreme judicial power was vested in the sovereign people in their comitia; that they delegated it in public matters to the senate, and in general legal cases to the praetor's court, but that in every capital charge a final appeal to them remained. The praetors at an early date handed over their authority to other judges, chosen either from the citizens at large, or from the body of _Judices Selecti_, who were renewed every year. These subsidiary judges might consist of a single _arbiter_, of small boards of three, seven, or ten, &c., or of a larger body called the _Centum viri_, chosen from the thirty- five tribes, who sat all the year, the others being only appointed for the special case. But over their decisions the praetor exercised a superior supervision, and he could annul them on appeal. The authorities on which the praetor based his practice were those of the Twelve Tables and the custom-law; but he had besides this a kind of legislative prerogative of his own. For on coming into office he had to issue an edict, called _edictum perpetuum_, [36] specifying the principles he intended to guide him in any new cases that might arise. If these were merely a continuation of those of his predecessor, his edict was called _tralaticium_, or "handed on." But more often they were of an independent character, the result of his knowledge or his prejudices; and too often he departed widely from them in the course of his year of office. It was not until after the time of Crassus and Antonius that a law was passed enforcing consistency in this respect (67 B.C.). Thus it was inevitable that great looseness should prevail in the application of legal principles, from the great variety of supplementary codes (edicta), and the instability of case-law. Moreover, the praetor was seldom a veteran lawyer, but generally a man of moderate experience and ambitious views, who used the praetorship merely as a stepping-stone to the higher offices of state. Hence it was by no means certain that he would be able to appreciate a complicated technical argument, and as a matter of fact the more popular advocates rarely troubled themselves to advance one.