Aurelian's many victories have calmed usurpation and sedition for a while.

Aurelian's enemies in the Senate briefly succeed n passing damnatio memoriae on the Emperor, but this is reversed before the end of the year and Aurelian, like his predecessor Claudius II, is deified as Divus Aurelianus.

Six months after the emperor's assassination—his widow, Ulpia Severina, having continued the government in the interim to become perhaps the only woman to rule over the whole Roman Empire in her own power—the elderly senator Marcus Claudius Tacitus is chosen by the Senate on short notice and the choice cordially ratified by the army.

This is to be the last time the Senate elects a Roman Emperor.

Tacitus, situated at Campania when he hears the news of his election, quickly rushes to Rome.

He decided to re-involve the Senate in some consultative manner in the mechanisms of government and asks the Senate to deify Aurelian, before arresting and executing Aurelian's murderers.

He makes his own half-brother, forty-three-year-old Marcus Annius Florianus, praetorian prefect, though the senate rejects him for a consulship.

By now, however, the Franks, the Alamanni, and a tribe called the Longiones (Lugii) are invading Gaul.

The Goths and the Heruli, the campaign against the Goths having been canceled with the murder of Aurelian, have once more crossed the Black Sea to wreak havoc on Asia Minor, plundering several towns in the Eastern Roman provinces.

Aurelian’s successor Tacitus, accompanied by his reported maternal half brother Marcus Annius Florianus, the Praetorian Prefect, leads the legions into Asia Minor and defeats the barbarians in battle in spring 276, which gains the emperor the title Gothicus Maximus.

He is on his way back west to deal with a Frankish and Alamannic invasion of Gaul when, (according to Aurelius Victor, Eutropius and the Historia Augusta), he dies in Tyana in Cappadocia in July.

It is reported that he began acting strangely, declaring that he would alter the names of the months to honor himself before succumbing to a fever.

In a contrary account, Zosimus claims he was assassinated, after appointing one of his relatives to an important command in Syria.

The Senate and the armies of the West tolerate the seizure, by Florian, of his late half-brother's' imperial position; however he mints coins bearing the "SC" legend, thus showing some bonds to the Senate.

Florian continues the campaign, driving the barbarians to the brink of defeat.

The legions in Syria, however, within two or three weeks promote their own general, Marcus Aurelius Equitius Probus, in opposition to Florian.

Probus, the son of a Balkan military officer, has served with distinction in the army and is now (apparently) eastern praetorian prefect.

He claims that Tacitus had meant him to be his successor.

Probus, on reaching Rome, receives the senate's confirmation him as emperor, and returns the favor by according the senators great respect, allowing them to conduct civil administration.

Under his regime, the surviving murderers of Aurelian are executed.