 Odaenathus observed all due <unk> towards the emperor , but in practice ruled as an independent monarch . In 266 , the king launched a second invasion of Persia but had to abandon the campaign and head north to <unk> to repel the attacks of <unk> riders besieging the city of Heraclea Pontica . He was assassinated in 267 during or immediately after the Anatolian campaign , together with Hairan . The identities of the perpetrator or the instigator are unknown and many stories , accusations and speculations exist in ancient sources . He was succeeded by his son Vaballathus under the regency of his widow Zenobia , who used the power established by Odaenathus to forge the Palmyrene Empire in 270 . 
