During the transition from republic to the Roman empire, the constitutional balance of power shifted from the Roman Senate back to the executive (the Roman Emperor). Theoretically, the senate elected each new emperor; in practice each emperor chose his own successor, though the choice was often overruled by the army or civil war. The powers of an emperor (his "imperium") existed, in theory at least, by virtue of his legal standing. The two most significant components to an emperor's "imperium" were the "tribunician powers" and the "proconsular powers". In theory at least, the tribunician powers (which were similar to those of the plebeian tribunes under the old republic) gave the emperor authority over Rome's civil government, while the proconsular powers (similar to those of military governors, or proconsuls, under the old republic) gave him authority over the Roman army. While these distinctions were clearly defined during the early empire, eventually they were lost, and the emperor's powers became less constitutional and more monarchical. The traditional magistracies that survived the fall of the republic were the consulship, praetorship, plebeian tribunate, aedileship, quaestorship, and military tribunate. Mark Antony abolished the offices of dictator and Master of the Horse during his Consulship in 44 BC, while the offices of Interrex and Roman censor were abolished shortly thereafter.