Assassination of Gallienus; Claudius II Succeeds

Gallienus had carried Rome through a decade of emergencies—plague, Edessa, the Gallic secession, and Gothic pressures. In 268, while besieging the usurper Aureolus at Mediolanum (Milan), his battlefield statecraft met the army’s new politics. In a night of hurried calls and flashing blades, conspirators struck inside the imperial circle. Gallienus, emperor since 253 (initially with his father Valerian), was killed [15][18].

The camp’s sounds turned from trumpet to alarm. Officers scrambled to impose order; the praetorian command sought an acclamation to fill the void before the legions fractured. Claudius, a Danubian officer with recent successes and a reputation for severity and clarity, emerged as the candidate. He was proclaimed—shields raised under torchlight, the purple clasp fastened over iron mail [14][18].

The new emperor faced immediate tasks. First, confirm the siege’s outcome and pacify northern Italy. Second, pivot quickly to the Balkan crisis. Gothic and allied forces had strained the line from Moesia to Thrace; Thessalonica felt pressed; Thermopylae had been hastily defended the year before [7][9]. Claudius reoriented the field army eastward, drawing units from the Po valley and along the Adriatic route toward Sirmium and Naissus.

In Rome, the senate received the news with a mixture of fatigue and relief. Gallienus’ long, embattled reign had accumulated enemies among elites; Claudius’ Danubian profile promised action. The mint continued its clatter at Rome and Lugdunum, striking radiates that bore a new face but the same alloy problems. Administrative continuity amid political rupture had become a Roman talent.

On the ground, Claudius’ appointment meant a concentration of force. The Goths—flush from raids and massing in strength—would soon face an emperor whose identity and honor depended on killing them. The crisis, so often diffuse, prepared to become pointed.