The Death of Constantius Chlorus (305 – 306) and the Collapse of the Tetrarchy

On November 20, 284, the army proclaimed Diocletian emperor of the Roman empire. He established a novel form of ruling, called tetrarchy (a four-ruler regiment). The first tetrarchy was established on March 1, 293, when Diocletian and Maximian Herculius were proclaimed Augusts and Galerius and Constantius Chlorus — Ceasars. On May 1, 305, the two Augusts abdicated, and then the second tetrarchy was established. Galerius and Constantius Chlorus were proclaimed Augusts and Maximin Daza and Severus became Ceasars. Maxentius, son of Maximian Herculius, and Constantin, son of Constantius Chlorus, were not on the list for Ceasars. The former did not stand out with his deeds, whereas Constantin was very popular among the soldiers and promoting him as Ceasar was a well-expected event. Constantius and his son resided in Britannia when Constantius died in York on July 25, 306. As a rule, Roman troops were loyal to the sons of their commanders and the Constantius Chlorus’s army was no exception. Straight after his death, they proclaimed Constantin August which marked the onset of new power struggles.