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.