Battle of Samarra The Battle of Samarra took place in June 363 , after the invasion of Sassanid Persia by the Roman Emperor Julian . A major skirmish , the fighting was indecisive but Julian was killed in the battle . The Romans , stranded deep in Persian territory and ran out of supplies , were forced to accept terms for peace . Context . Julian invaded Persia with a force of 65 , 000 men , hoping to win a major victory against Persians in the east and replace Shah Shapur II with his brother Ormisdas . Julian made two blunderous mistakes at the very onset of the invasion . He split his force into two , one under General Procopius numbering 30 , 000 men , which went to northern Mesopotamia , and one numbering 35 , 000 men under his own leadership . His second mistake was not defeating the main Sassanid army before attacking the capital , which would eventually lead to expedition ' s failure in 363 . Julian at first won a tactical victory outside Ctesiphon , but could not take the city . Even worse , Prokopius failed to join him with his army , for unknown reasons . David S . Potter suggests that Julian ' s main faults was that he made a very risky campaign and that he didn ' t bring adequate siege train . Therefore , he had to retreat after realizing that Ctesiphon was too strongly defended to be taken by assault while his army was running out of supplies . However , the Sassanid army , under Shapur , implemented a scorched earth policy while harassing Romans all their way back to Roman Mesopotamia . Julian , realizing that his army could not get resupplied or re - enforced , tried to commence a set piece battle with his enemy , but could not . So decision was taken to retreat through the district of Corduene to the north , where there was hope to find adequate supplies . After a few days of advancing through the enemy country , despite defeating Persian skirmishes and inflicting them heavy losses in the Battle of Maranga , the demoralized army was essentially depleted of provisions and tired of the continuous fighting . The battle . After three quiet days , the Roman army was attacked during its cautious advance in square formations . The battle at Samarra was a Persian skirmish , first against the rear guard of the Roman column . Then they fell on the center and the left wing of the Romans . According to Ammianus Marcellinus narrative , Julian hastened to rally his forces against the Persians , without wearing his armor . He managed to raise their morale and reverse the possibility of collapsing but his personal guard was dispersed during the fighting and Julian was fatally hit on his back by a spear . The spear was most probably thrown by a Saracen auxiliary in Persian service , as his doctor Oribasius concluded . After treatment by the doctors , he returned to the battlefield . The battle continued indecisively until the darkness of the night put an end to the fighting . According to another view , the Roman army was defeated by the Persian forces . Julian died from his wound , in his tent , a few hours later . Aftermath . The Roman army ' s general staff proclaimed Jovian , the commander of Julian ' s guard , as his successor . He led his army to the east bank of Tigris , under continuous harassing from the Persians , and suffered heavy losses . After failing to cross the Tigris , Jovian clearly saw that the situation was desperate . Thus he was forced to accept humiliating terms from Sapur , in order to save his army and himself from complete destruction . The treaty with Shapur included surrendering Eastern Mesopotamia , Georgia and Armenia , as well as fifteen fortresses , including the strategic cities of Nisibis and Singara , without their inhabitants . This severely hampered the empire ' s defensive system in the east and gave the Persians favorable conditions in their subsequent confrontations with the Romans .