You might recognize our saint from Eucharistic Prayer I:
"your blessed Apostles and Martyrs,
Peter and Paul, Andrew,
(James, John, Thomas, James, Philip,
Bartholomew, Matthew, Simon and Jude;
Linus, Cletus, Clement, Sixtus,
Cornelius, Cyprian, Laurence, Chrysogonus,
John and Paul, Cosmas and Damian)
and all your Saints;"
Cornelius was reluctantly elected pope during a fairly rough period of persecutions for the Church. The turmoil and fear caused division, apostasy, and heresy. In his short two year reign he worked hard against all these things, establishing himself as the legitimate pope and authority, teaching against Novatian and welcoming back those who had denounced their faith our of fear in opposition to him, all helping to keep the Church one, holy, catholic, and apostolic - and practicing the forgiveness of sins that is so central to our Faith.
Pray for our pope, bishops, priests, deacons, and religious that they may remain faithful teachers and practitioners of the Faith.
Do not waste your time and your words on us. We are people endowed with reason, for whom it would be the greatest disgrace to abandon the one true God, the Maker of heaven and earth, in order to worship dumb, senseless idols. We are not afraid of torments you threaten us with. They will be easy for us to bear and will show the power of our God.
-- Saint Euphemia, in response to the Proconsul of Asia Priscus' attempt to persuade them to sacrifice to Mars (also celebrated today)