Magister equitum

In the time of the Roman Kingdom, the king himself would lead the cavalry into battle, or else delegate this authority to his chief advisor, the Tribune of the Celeres, the cavalry unit that also served as the king's personal bodyguard. The last person to hold this position was Lucius Junius Brutus, nephew of Lucius Tarquinius Superbus, the seventh and final King of Rome. After the rape of Lucretia, it was Brutus who, in his capacity as Tribune of the Celeres, convened the comitia, and brought about the abrogation of the king's imperium. Following the expulsion of Tarquin, Brutus, whom the comitia elected one of the first consuls, commanded the cavalry in the Battle of Silva Arsia, where he fell, BC 509. In the early years of the Republic, no attempt was made to reconstitute the office of Tribune of the Celeres; the supreme military authority was vested in the consuls. In keeping with the principle that no one man should hold the full power of the Roman state, it was possible to appeal the decisions of one consul to the other. However, in the ninth year of the Republic, war appeared imminent with both the Latin League, led by the exiled king's son-in-law, Octavius Mamilius, and the Sabines, with whom the Romans had fought in 505 and 503 BC. At the same time, there was suspicion that the consuls harbored royalist sympathies. In the face of this panic, the Romans resolved to appoint a praetor maximus, or dictator, as the office came to be called, from whom there should be no right of appeal, for the duration of the emergency. The consul Titus Lartius Flavus was nominated the first dictator, and Spurius Cassius Vecellinus the first magister equitum. Alarmed by this development, the Sabines sent envoys to Rome to negotiate peace. The Latins were not yet ready for war, and thus the dictator and magister equitum were able to lay down their office without taking the field. ==Nature of the office==

The powers of the ancient Tribune of the Celeres were thus divided and limited from the institution of the dictatorship. Although the dictator commanded the entire army, his technical title was magister populi, or "master of the infantry", while the cavalry was entrusted to his lieutenant. Although the original function of the dictator was to lead the Roman army in time of war, a dictator was sometimes nominated for the purpose of holding elections, restoring order, or performing vital religious functions when it was impossible for the consuls or other magistrates to do so. In these cases, it was still customary for the dictator to appoint a magister equitum to serve as his lieutenant. ==History==

Before the institution of the praetorship, it was common for the magister equitum to be someone who had already served as consul or consular tribune. In this way, the magistracy was held by someone who had prior experience with military command. For those who had yet to achieve the highest offices of the Roman state, this appointment was a valuable stepping stone toward those offices. On the outbreak of civil war between Caesar and Pompeius in 49 BC, Caesar was appointed dictator for purposes of holding the elections; no magister equitum was nominated. Dictator for the second time in 47, Caesar made Marcus Antonius his master of the horse, followed by Marcus Aemilius Lepidus, whom Caesar reappointed in February 44. Caesar designated Gnaeus Domitius Calvinus to be the next magister equitum and possibly Caesar's nephew Gaius Octavius to follow him in 42, but in March 44 the dictator was assassinated before either designate could take office. With the consolidation of power first under the triumvirate of Octavian, Antonius, and Lepidus, and then in the person of Octavian alone, no further dictators were appointed. Following Caesar's death, Antonius promulgated a law abolishing the office. His successors followed his example; even when they assumed the powers of a dictator, they never assumed the title or appointed a master of the horse. Thus, the ancient title of magister equitum fell once more into abeyance. Both roles continued to be used as military administrators of Byzantine praetorian prefectures. ==List of magistri equitum==