Reluctantly, Julian agreed to retreat back along the Tigris and look for Procopius and the other half of his army that had failed to coordinate the double-pincers movement with him outside of Ctesiphon as had been planned. On June 16, 363, the retreat began. Ten days later, after an indecisive Roman victory at Maranga, the army’s rearguard came under heavy attack, in the Battle of Samarra.