The Roman emperor Caracalla was assassinated on the road from Edessa to Carrhae (now Harran) by one of his guards in 217. Edessa became one of the frontier cities of the province of Osroene and lay close to the border of the Sasanian Empire. The Battle of Edessa took place between the Roman armies under the command of the emperorValerian and the Sasanian forces under emperor Shapur I in 260. The Roman army was defeated and captured in its entirety by the Persian forces, including Valerian himself, an event which had never previously happened.