The two new magistrates, who were appointed to the headship of the state, were, like the king, armed with the _imperium_ and its united powers of military leadership and jurisdiction. Hence they bore the old titles of _praetores_ and _judices_,[316] while those designations which denoted a single supremacy in the state, such as _dictator_ or _magister populi_, were necessarily discarded. The new magistrates were to hold office for a year and then to transmit their power to two successors. But their right of nomination was not final. They were, indeed, free to name as their successors whom they pleased, but this nomination had to be ratified immediately by the people assembled in their centuries; and perhaps they were already expected to submit to this _comitia_ the names of all candidates who offered themselves for this post, although they could certainly decline to receive such names,[317] and nomination, or, as it was sometimes called, _creatio_, was an essential part of the early consular elections. A new practice, that of direct election, was thus introduced into the Roman constitution, but it was merely an advance on the previous practice of ratifying a nomination.[318] A far newer idea—one which distinguished the consulship from the monarchy, and continued to differentiate it from the dictatorship subsequently created—was that of _colleagueship_,[319] of two officials exercising exactly the same sphere of competence, with the inevitable effect of collision if agreement could not be secured. Perpetual collision was averted by the simple rule that the dissent of one magistrate rendered null and void the action of his colleague. But if such dissent was not expressed (or not capable of expression through the absence of the colleague) the command of a single magistrate had binding force on the community. His regal competence was not diminished, but only potentially checked, by the presence of a colleague. Colleagueship, considered as the safeguard against abuse of the _imperium_, grew to be so firmly impressed on popular imagination as the characteristic feature of the new office, that the earlier titles derived from the monarchy gave place to that of _consules_.[320]