Shapur I's rule was marked by successful military and political struggles in the northeastern regions and the Caucasus, and two wars with the Roman Empire during the second of which he captured the Roman Emperor Valerian and his entire army at the Battle of Edessa.
From his titles we learn that Shapur I claimed sovereignty over the whole earth, although in reality his domain extended little farther than that of Ardashir I.
"Shapur" was a popular name in Sasanian Iran, being used by three Sasanian monarchs and other notables of the Sasanian era and its later periods. Derived from Old Iranian *xšayaθiya. puθra ("son of a king"), it must initially have been a title, which became-at least in the late 2nd century AD-a personal name.
During the reign of Shapur, Manichaeism, a new religion founded by the Iranian prophet Mani, flourished. Mani was treated well by Shapur, and in 242, the prophet joined the Sasanian court, where he tried to convert Shapur by dedicating his only work written in Middle Persian, known as the Shabuhragan.
They offered freedom to slaves who rebelled and reached Spanish territory.
Goods shipped by sea enjoyed the protection of the English Navy.