Imperium
The full kingly power among the Romans, the royal authority over all members of the State. It was conferred on the newly-elected king by the Comitia Curiata, a formal assembly of the patricians comprising the curiae, and it consisted of the rights of levying the citizens for military service, of leading the army, of celebrating a triumph, of exercising civil and criminal jurisdiction, and of inflicting punishment on the citizens, whether corporal or capital, or such as affected either their property or their liberty. A symbol of this authority was the axe and the bundle of rods borne by the lictors. See Fasces.At the establishment of the Republic the imperium was transferred to the two consuls, as the successors of the kings; but the full power of the imperium was then limited by the fact that both possessed the same power, and that, in the penalties they inflicted in times of peace, they were subject to the right of appeal (see Provocatio), and to the intervention of the tribunes of the people, after the institution of that office. When the consulship was deprived of its civil jurisdiction and the praetorship instituted for this purpose, the praetors also received the imperium; nevertheless it was more limited (minus) than that of the consuls, who, in contrast with the praetors and all other magistrates except the tribunes, had the right of ordering and forbidding. The imperium in its undivided and unlimited form was conferred on those who in exceptional cases were appointed dictators. It was also possessed by the interrex, but for five days only. For consuls and praetors the imperium could be prorogued, i. e. prolonged beyond their time of office; but the imperium thus prolonged was finitum, i. e. bounded within the limits of their province. In the Republic it could also be conferred by means of the Comitia Curiata, but this act fell into a mere formality. Under the Empire the term imperium included the highest military authority, which resided in the emperor and was the foundation of all his power. It was taken up either at the instance of the Senate or the troops. Its full validity depended on its recognition by both. See Princeps.