St. Eusebius' feast on the traditional Catholic calendar is today. He was Bishop of Vercelli, Italy, and lived from about A. D. 283 - 371. He is considered a martyr for the persecutions he experienced by the Arians while in exile. Thus he defended the divinity of Jesus.
One noticeable aspect in following the church calendar is how many martyrs there are. Interestingly, the number of martyrs at the time of the early church does not compare with the number of martyrs during the 20th c. We hear also how Christianity is the most persecuted religion world-wide today.
From the Mass Sacerdotes Dei: Blessed be the God and Father of our Lord Jesus Christ, the Father of mercies and the God of all comfort, who comforteth us in all our tribulation . . ." (Epistle)