Septimius Odaenathus was the founder king of the Palmyrene Kingdom who ruled from Palmyra, Syria. He elevated the status of his kingdom from a regional center subordinate to Rome into a formidable state in the Near East. Odaenathus was born into an aristocratic Palmyrene family that had received Roman citizenship in the 190s under the Severan dynasty. He was the son of Hairan, the descendant of Nasor. The circumstances surrounding his rise are ambiguous; he became the lord of the city, a position created for him, as early as the 240s and by 258, he was styled a consularis, indicating a high status in the Roman Empire.
The defeat and captivity of Emperor Valerian at the hands of the Sassanian emperor Shapur I in 260 left the eastern Roman provinces largely at the mercy of the Persians. Odaenathus remained on the side of Rome; assuming the title of king, he led the Palmyrene army, fell upon the Persians before they could cross the Euphrates to the eastern bank, and inflicted upon them a considerable defeat. He took the side of Emperor Gallienus, the son and successor of Valerian, who was facing the attempted usurpation of Fulvius Macrianus.