of Mesopotamia to be loyal to Shapur I. By late 262 or early 263, Odaenathus stood outside the walls of the Persian capital. The exact route taken by Odaenathus from Palmyra to Ctesiphon remains uncertain; it was probably similar to the route Emperor Julian took in 363 during his campaign against Persia. If he did use this route, Odaenathus would have crossed the Euphrates at Zeugma then moved east to Edessa followed by Carrhae then Nisibis. Here, he would have descended south along the Khabur River to the Euphrates valley and then marched along the river's left bank to Nehardea. He then penetrated the Sassanian province of Asōristān and marched along the royal canal Naarmalcha towards the Tigris, where the Persian capital stood. Once at Ctesiphon, Odaenathus immediately began a siege of the well-fortified winter residence of the Persian kings; severe damage was inflicted upon the surrounding areas during several battles with Persian troops. The city held out and the logistical problems of fighting in enemy territory probably prompted the Palmyrenes to lift the siege. Odaenathus headed north along the Euphrates carrying with him numerous prisoners and much booty. The invasion resulted in the full restoration of the Roman lands which had been occupied by Shapur I since the beginning of his invasions in 252: Osroene and Mesopotamia. However, Dura-Europus and other Palmyrene posts south of Circesium, such as Anah, were not rebuilt. Odaenathus sent the captives to Rome, and by the end of 263 Gallienus assumed the title Persicus maximus ("the great victor in Persia") and held a triumph in Rome. King of Kings of the East In 263, after his return, Odaenathus assumed the title of King of Kings of the East (Mlk Mlk dy Mdnh), and crowned his son Herodianus (Hairan I) as co-King of Kings. A statue was erected and dedicated for Herodianus to celebrate his coronation by Septimius Worod, the duumviri (magistrate) of Palmyra, and Julius Aurelius, the Queen's procurator (treasurer). The dedication, in Greek, is undated, but Septimius Worod was a duumviri between 263 and 264. Hence, the coronation took place c. 263. Contemporary evidence for Odaenathus bearing the title of King of Kings is lacking; all firmly dated inscriptions attesting Odaenathus with the title were commissioned after his death, including one that is dated to 271. However, Herodianus died with his father, and since he is directly attested as "King of Kings" during