What is the name of the ill-fated emperor captured in battle at Edessa in 253 A.D.?

The name of the ill-fated emperor captured in battle at Edessa in 253 A.D. is Valerian. His reign was marked by a series of challenges, including external threats from the Persian Empire. During a military campaign against the Sassanids, Valerian encountered a significant defeat which led to his capture, making him the first Roman emperor to be captured as a prisoner of war. This event had lasting implications for the Roman Empire and its military reputation, and Valerian's subsequent treatment as a captive by the Persian king is historically significant.

In contrast, Gallienus was Valerian's son and co-emperor who ruled after him. Diocletian came to power later, during the Tetrarchy in the late 3rd century, and Marcus Aurelius was a philosopher-king whose reign occurred in the late 2nd century, long before Valerian's rise. Therefore, the accurate association of Valerian with the capture at Edessa is crucial in understanding the historical context of the Roman Empire during that period.