Valentine of Terni is traditionally said to have been persecuted under Roman Emperor Aurelian in 273.
This tradition belongs to the hagiography of Valentine of Terni, who is described as a Christian bishop from Interamna, the ancient city now known as Terni. According to the story, he was arrested, tortured, and ultimately martyred during a period of imperial persecution.
The date and circumstances are not supported by detailed contemporary records. Accounts of Saint Valentine were written later and contain legendary material, so historians distinguish between traditional claims and firmly documented biography. The wording “is said to have” appropriately signals that uncertainty.
A major source of confusion is Claudius II, who appears in legends about Valentine of Rome. Diocletian is also famous for persecution of Christians, but the specific traditional association in this question is Valentine of Terni with Aurelian and the year 273.