Nereus and Achilleus were Roman soldiers in the household of Flavia Domitilla. They were instructed and baptized by St. Peter. These two soldiers admired Domitilla, and began to tell her about the Christian faith. They helped her to understand her own human dignity, and she decided that she really wanted to give herself to Christ completely, and that she wouldn’t marry. Upon learning this, Aurelianus reported all three to the Roman authorities as being Christians. They were beheaded, martyred out of hatred for the Christian faith.
Domitilla owned some property outside the city of Rome, and she had given this land to the Christians as a cemetery, and to this day it is the site of one of the major catacombs. Nereus, Achilleus, and Domitilla were buried there.
Grant, O Lord, that this holy festival of thy blessed Martyrs, Nereus and Achilleus, may ever assist us in thy service: and that we may thereby be rendered worthy to walk after thy commandments; through Jesus Christ thy Son our Lord, who liveth and reigneth with thee, in the unity of the Holy Spirit, ever one God, world without end. Amen.