Christians were persecuted in 250 AD under the Roman emperor Decius. He had issued an edict ordering everyone in the empire to perform a sacrifice to the Roman gods and the well-being of the emperor. The sacrifices had to be performed in the presence of a Roman magistrate, and be confirmed by a signed and witnessed certificate from the magistrate. Although the text of the edict has been lost, many examples of the certificates have survived.
Decius' edict was intended to act as an empire-wide loyalty oath to the new emperor (who had come to power in 249 AD), sanctified through the Roman religion. Christian monotheistic beliefs did not allow them to worship any other gods, so they were forced to choose between their religious beliefs and following the decree.