Valentinian I came to power in 364 CE, and one month later named his brother Valens as his co-Augustus. In this arrangement, Valentinian held control of the West while Valens ruled over the eastern provinces. Valentinian fought successfully against the Alamanni, Quadi, and Sarmatians and because of his military accomplishments is often hailed as the last great western emperor. The vexillum he holds on the reverse of this coin is a Roman military ensign, or cavalry standard. It was an object of religious veneration amongst the soldiers who paid it divine honors. Constantine the Great converted this banner into a Christian symbol using the monogram ☧ (a Greek chi and rho, the first two letters of "Christ" in Greek) seen here. The message of "restoration" was important early in Valentinian's reign because of his need to restabilize the empire after a major setback for Roman forces in Persia under Julian. Christina Dickerson 2011.