The legend being widely propagated by these apocryphal Acts, Petronilla was identified at Rome with this supposed daughter of St. Peter, probably because of her name and the great antiquity of her tomb. As such, but now as a virgin, not as a martyr, she appears in the legendary Acts of the martyrs St. Nereus and Achilleus and in the "Liber Pontificalis". From this legend of Sts. Nereus and Achilleus a similar notice was admitted into the historical martyrologies of the Middle Ages and thence into the modern "Roman Martyrology".