“On the Firmness of God’s Word and the Rottenness of Bulgarian Folly” (The Martyrdom of the Fifteen Martyrs of Tiberioupolis and the Christianization of Bulgaria) Read more about “On the Firmness of God’s Word and the Rottenness of Bulgarian Folly” (The Martyrdom of the Fifteen Martyrs of Tiberioupolis and the Christianization of Bulgaria)