Battle of Callinicum The Battle of Callinicum took place Easter day , 19 April 531 , between the armies of the Eastern Roman Empire under Belisarius and the Sassanid Persians under Azarethes . After a defeat at the Battle of Dara , the Sassanids moved to invade Syria in an attempt to turn the tide of the war . Belisarius ' rapid response foiled the plan , and his troops pushed the Persians out of Syria through skillful maneuvering before forcing a battle . Battle . In April 531 , a Persian force under Azarethes , numbering about 15 , 000 cavalry , with an additional group of 5 , 000 Lakhmid Arabs , crossed the frontier at Circesium on the Euphrates and marched north . As they neared Callinicum , Belisarius , who commanded the local Byzantine troops , set out to follow them as they advanced westwards . Belisarius ' forces consisted of about 5 , 000 men and another 3 , 000 Ghassanid Arab allies , for the remainder of his army had been left to secure Dara . The Byzantines finally blocked the Persian advance at Chalcis , where reinforcements under Hermogenes also arrived , bringing the Byzantine force to some 20 , 000 men . The Persians were forced to withdraw , and the Byzantines followed them east . Initially , Belisarius only wanted to drive off the Persians , without a risky battle . The Byzantine troops , however , were restless , and clamored for battle . After failing to convince his men , and realizing they would mutiny unless he agreed , Belisarius prepared his force for battle . The two armies met outside Callinicum on 19 April 531 . Both groups formed up differently , Belisarius again choosing an " odd " formation that confused his opposing general . In this case he anchored his left flank on the bank of the river with infantry , put the Ghassanid Arab allies on the right flank , and placed several ranks of heavy cavalry , the cataphract s , in the center of the front line . In more standard formation the Persians split their forces into two roughly equal groups , with infantry in front of cavalry . For much of the day , the battle was a stalemate , with the Persians and Byzantines trading arrows and cavalry charges . After " two thirds of the day " had elapsed a squadron of the elite Persian cavalry broke through the Roman right flank , composed of Belisarius ' Ghassanid allies , with surprising force such that the Ghassanids were accused of treachery after they fled . With his right flank gone , Belisarius was forced to retreat in an effort to re - form his line , but the retreat was followed and soon the Romans found themselves pressed against the river . Zacharias of Mytilene says of this battle : " " [ The Romans ] turned and fled before the Persian attack . Many fell into the Euphrates and were drowned , and others were killed . " " However , it is unknown what stage of the battle Zachariah was referring to . Here on the river , the Romans were able to resist the Persians and withdraw much of their army across the river . The Persians attacked the Byzantine lines over the course of several hours , killed many resisting Roman troops , and inflicted heavy casualties on them . Eventually , the Romans gave up , and Belisarius fled with his soldiers . Outcome . The direct outcome of the battle was something of a stalemate ; the Byzantine army had lost many soldiers and would not be in fighting condition for months , but the Persians had taken such heavy losses that it was useless as to its original purpose , the invasion of Syria . Upon return , Emperor Kavadh I removed General Azarethes from command and stripped him of his honors due to the general ' s actions in the battle . This mutual disaster was the first of Belisarius ' series of ( relatively ) unsuccessful wars against Sassanids , which led Byzantine to pay heavy tributes in exchange for a peace treaty and the remaining Byzantine land still in Persian hands . Callinicum ended the first of Belisarius ' Persian campaigns , returning all of the land lost to them to Roman rule under Justinian I in the Eternal Peace agreement signed in summer 532 .