Bahram II was the fifth Sasanian King of Kings (shahanshah) of Iran, from 274 to 293. He was the son and successor of Bahram I. Bahram II, while still in his teens, ascended the throne with the aid of the powerful Zoroastrian priest Kartir, just like his father had done.

Diocletian, nicknamed Jovius, was Roman emperor from 284 until his abdication in 305. He was born Diocles to a family of low status in the Roman province of Dalmatia. Diocles rose through the ranks of the military early in his career, eventually becoming a cavalry commander for the army of Emperor Carus. After the deaths of Carus and his son Numerian on a campaign in Persia, Diocles was proclaimed emperor by the troops, taking the name Diocletianus. The title was also claimed by Carus's surviving son, Carinus, but Diocletian defeated him in the Battle of the Margus.