Catholic Encyclopedia

SS. Nereus and Achilleus, Domitilla and Pancratius, Roman martyrs who shared a feast day on 12 May. Nereus and Achilleus are martyrs of the first or early second century, and were buried in the Catacomb of Domitilla. Pancratius was martyred most likely in either the Valerian or Diocletian persecution. Domitilla comes into the story because later authors assumed that Nereus and Achilleus must have had some connection with her to be buried in the catacomb that bears her name.