The last Roman emperor elected by the Senate. 25 September, 275.

Marcus Claudius Tacitus Augustus, known as Tacitus, was the last Roman emperor elected by the Roman Senate, and served only for a short period of time, between 275 and 276 AD.

Little is known about Tacitus´ career before his reign. Some sources suggest he served in the Danube Legions before becoming a senator. We do know he held the office of Senate consul, rising to the highest Senate rank, princeps senatus, an office he held at the time he reluctantly accepted to be the next emperor by acclaim of the Senate.

After the assassination of Aurelian, an eight-month long interregnum took place. During this time, the army, who normally would proclaim the next emperor,  decided to cede their right to the Senate, due to their remorse over the death of the popular emperor, Aurelian, who had died without naming a successor. On September 275, the Senate voted, and the respected Tacitus was elected the new emperor. Tacitus was already 75 years old, and was reluctant to accept the offer. After ascertaining the sincerity of the Senate’s regard for him, Tacitus accepted their nomination on 25 September 275, and the choice was cordially ratified by the army. This would be the last time the Senate elected a Roman Emperor.

During Tacitus´ reign the Senate recovered the political power that they had held in past times. Gallienus´ edict that forced a separation between the senators and the military offices was revoked. Tacitus was hence favored by the philo-senatorial historiographers, who idealized his image of “good emperor”, as well as his reputation as a freedom-restorer.

In 276, a Goth and Scythian incursion in Asia Minor forced Tacitus to rally his troops. The emperor, together with his half-brother Florianus (whom he had named Praetorian Prefect), managed to stop the enemies in the region of Cilicia, for which he received the title of Gothicus Maximus. While returning to Rome, Tacitus died suddenly in Tyana. Whether he was assassinated or it was a natural death remains a mystery. After his death, his brother Florianus was proclaimed emperor, recognized by a majority of the army who reclaimed the right to name the next emperor. Nevertheless, rebellious troops from Syria and Egypt proclaimed Probus, their chief-commander, emperor. Both sides confronted each other in Tarsus, but Florianus was betrayed by his own army and assassinated.