Odaenathus: conqueror of the Persians
As early as the 230s, the Sassanid Persians - who replaced the Parthians in Mesopotamia and Iran in 224-226 - launched a series of devastating attacks against Syria. When the emperors proved incapable of protecting the province, a Roman senator from Palmyra, Odaenathus, took the lead in its defence in the early 250s. With his eldest son Hairan, he succeeded in inflicting several defeats on the Persians (259) and pursued them as far as the walls of their capital Ctesiphon (260), supported by the militia of Palmyra and Roman troops.
Odaenathus: loyal to Rome
Inscriptions from Palmyra recount his successes and titles, all Roman and granted by the emperor, except one, “King of Kings”, in direct defiance of his vanquished enemy, the Persian king Shapur. He held no particular power in Palmyra, which remained a Roman colony, and there is no suggestion he wished to break with Emperor Gallienus. In 267 or 268, he was murdered with his son Hairan in uncertain circumstances.
His second wife, Zenobia, immediately transferred the title of "King of Kings" to her son Wahballath, a child or teenager under her guardianship; he also received the Roman titles, including the military titles of dux and imperator, to assert his continued loyalty to Rome.
The guardianship of Zenobia
After the death of Gallianus in 268, and under the reign of Claudius II Gothicus (268-270), Zenobia extended her control over all the eastern provinces, the three Syrian provinces, Arabia, conquered by force, and then Egypt in 270. Although the name Wahballath began to appear on milliaria (in principle an imperial privilege) from this point onwards, there is still no evidence of a formal usurpation of the imperial title.