The Feast of St. Irenaeus of Lyons, Bishop and Martyr
is today. There is information on him here.

Take a large view of the faith of Christians during the centuries before Constantine established their religion. Is there any family likeness in it to Protestantism? Look at it, as existing during that period in different countries, and is it not one and the same, and a reiteration of itself, as well as singularly unlike Reformed Christianity? Hermas with his visions, Ignatius with his dogmatism, Irenæus with his praise of tradition and of the Roman See, Clement with his allegory and mysticism, Cyprian with his "Out of the Church is no salvation," and Methodius with his praise of Virginity, all of them writers between the first and fourth centuries , and witnesses of the faith of Rome, Africa, Gaul, Asia Minor, Syria, and Egypt, certainly do not represent the opinions of Luther and Calvin. They stretch over the whole of Christendom; they are consistent with each other; they coalesce into one religion; but it is not the religion of the Reformation. When we ask, "Where was your Church before Luther?" Protestants answer, "Where were you this morning before you washed your face?" But, if Protestants can clean themselves into the likeness of Cyprian or Irenæus, they must scrub very hard....

Venerable John Henry Newman, Historical Sketches, Volume I


It is also the feast of Pope St. Paul I, and St. John Southworth, Priest and Martyr.