It is difficult to know what to make of the Emperor Licinius. Co-emperor with Constantine, he was also co-author of the Edict of Milan, which granted toleration to Christianity. Like Constantine, he seems to have provided some support for Christians in the Empire. But there are plenty of reports of persecutions of Christians under his watch. Some of these may be more political than real, since it was in Constantine's political interest to paint Licinius as a thoroughly anti-Christian pagan; but there are enough reports of sufficient repute to give us reason to think that a number of them are real. Among these are the Forty Martyrs of Sebaste. The Forty Martyrs were soldiers of the Legion XII Fulminata, stationed in Armenia; they were exposed naked on a frozen pond throughout the night and then burned. This is said to have happened in 320; we know, because of a homily by St. Basil, that they already had a church dedicated to them in Caesarea and a regular feast-day by the 370s.
Devotion to the Forty Martyrs became quite popular very quickly, then, and also entangled with the customs of Lent early on -- St. Gregory of Nyssa notes the play on the number of forty in a homily probably from no later than the early 380s, and the memorial can be seen as a reminder that every day of Lent is a little martyrdom.
Feast of the Forty Martyrs of Sebaste
2 Corinthians 4:11-18; Luke 6:20-23
It is pleasing in the eyes of God
to recall His martyrs with joy,
to celebrate their memorials,
to sing their deeds with hymns and songs;
what satiety of remembrance
can there be for those who love them?
The martyrs rain down help upon us;
like bulwarks they protect our walls,
protect us from the inroads of sin.
Their death is for our sake, for grace,
that we may have thanksgiving to God.
Their light trouble has eternal weight;
the seen fades soon, not their victory.
To the Lord you said, "We are forty,
engaged in a mighty combat;
grant that we may win to the great crown,
grant that not one of us may fail."
Rejoice and leap for joy, O martyrs;
you are witnesses to his grace.
Happy are you when people hate you,
when they revile you and spurn you,
because of the kingdom of Heaven!
Rejoice in that day, leap for joy;
your reward will be great in Heaven.
The Lord said "Follow," and you followed,
O Forty Martyrs of Sebaste.