Marcus Clodius Pupienus Maximus and Decius Caelius Calvinus Balbinus (both died 238) were elected co-emperors by the Roman senate in 238 after the failing of Gordian I and Gordian II in defeating the usurper Maximinus Thrax.
Pupienus, born about 178, was an example of ascension in the Roman hierarchical system due to military success. He started as a primus pilus, a military tribune, praetor, twice consul and governor of several Roman provinces including the problematic Germania Inferior. In 234 he was prefect of Rome and gained a reputation of severity.
Balbinus was of equal shared his consular status and political clout. As Pupienus, he belonged to a special senatorial commission to deal with the Maximinus Thrax problem. The usurper emperor had been declared public enemy and, after the defeat in Africa of the senate's candidates, Gordian I and Gordian II, was marching on Rome. Without other candidates in view, the senate elected Pupienus and Balbinus joint emperors. The grandson of Gordian I and future Gordian III was nominated Caesar to appease the population of Rome. Pupienus is sent at the head of an army to face Maximinus and Balbinus stays in Rome.
Meanwhile, Maximinus situation was not easy. Discontentment due to the lack of supplies and the strong opposition of the senate, forced his legionaries to rethink their alliance. Soldiers of the Legio II Parthica kill the usurper and surrender to Pupienus in the end of June. The co-emperor then returns to Rome, only to find the city in riot. Balbinus had not managed to control the situation and the city had burned in a fire resulting on the mutiny. With both emperors present the situation calms down but the unease remains.
The relation between Balbinus and Pupienus had been clouded with suspicion from the start, with both fearing an assassination from the other. They were planning an enormous double campaign, Pupienus against the Parthians and Balbinus against the Germanic tribes, but they quarrelled frequently. It was during one of these heavy discussions, on July 29, that the Praetorian guard decided to intervene. They stormed in the room were the emperors were and killed them both. On the same day, Gordian III, only 13 years old, is proclaimed emperor.
Together they ruled a little more than three months. Coins from their short reign show their either one of them in one face and two clasped hands in the other to show their joint power.
Gordian I and Gordian II (238)
Gordian III (238 - 244)