The Roman Republic began exercising political influence over the Kingdom of Osroene and its capital Edessa from 69 BC. It became a Roman "colonia" in 212 or 213, though there continued to be local kings of Osroene until 243 or 248. In Late Antiquity, Edessa was an important city on the Roman–Persian frontier with the Sasanian Empire. It resisted the attack of Shapur I () in his third invasion of Roman territory. The 260 Battle of Edessa saw Shapur defeat the Roman emperor Valerian () and capture him alive, an unprecedented disaster for the Roman state. The Late Antique "Laterculus Veronensis" names Edessa as the capital of the Roman province of Osroene. The Roman soldier and Latin historian Ammianus Marcellinus described the city's formidable fortifications and how in 359 it successfully resisted the attack of Shapur II ().