This marks the beginning of Shapur's I second invasion of the Roman empire which saw the first Sassanid invasion of Syria; the year of the invasion is debated as Shapur's inscription from Naqsh-e Rustam regarding his second campaign against Rome do not mention the city of Nisibis. But Syriac and Arabic sources, mainly the Chronicle of Seert and Al-Tabari, mention that Shapur took Nisibis in his eleventh regnal year; according to the historian David Stone Potter, this regnal year is 252. Another Syriac account, the Liber Caliphorum, from the eighth century, mentions the invasion of the city in 252.[3][4]