A extremely fine coin commemorating the Roman "victory" at the Battle of Singara -- the legionary fortress-city of Legio I Parthica in modern day Iraq -- in 344 CE. The Roman army, under the personal command of Constantius II, claimed to have defeated the Sassanid army led by Shapur II, but its probable that Shapur simply abandoned the siege of Singara, leaving the Romans in control of the field. Despite the reality of a Pyrrhic victory, the imperial government issued these coins to propagandize the Roman defense of Singara. Ironically, the Persians would return in 360 CE and successfully take Singara. This coin also bears the christogram emblazoned on the military banner being held by Constantius II. According to the Roman historian Eusebius, before the Battle of the Milvian Bridge Constantine saw a cross of light imposed over the sun. Attached to it, in Greek characters, was the saying "Ev tούτῳ Νίκα!" ("In this, conquer!"). That night, Christ appeared to the Roman emperor in a dream. The next day Constantine instructed his soldiers to paint the Chi-Rho symbol ( also called a christogram) on their shields and assured them that as long as they did this they'd be victorious. Constantine defeated Maxentius.The Chi-Rho symbol would go on to become ingrained in Roman iconography.