A busy day in church history:

155 The martyrdom of Polycarp of Smyrna.
Polycarp (69-155) was a bishop of Asia Minor who had, according to tradition, studied under St. John, the last of the original Twelve Apostles, thus an important link between primitive Christianity and the expanding Church. Called upon to apostatize and worship the imperial cult, Polycarp refused, saying: “Eighty and six years I have served Him, and He has done me no wrong. How then can I blaspheme my King and Saviour? You threaten me with a fire that burns for a season, and after a little while is quenched; but you are ignorant of the fire of everlasting punishment that is prepared for the wicked.” He was burned at the state. He is the patron saint of those suffering from dysentery and earache.

303 The Beginning of the Great Persecution
Christianity had been intermittently subject to persecution since its inception but there were two periods of intense and focussed attempts to exterminate the new religion, one in the mid-3rd century under the emperor Decius and, the second and most murderous, under Diocletian beginning on this date in 303 when he attacked the church in the eastern capital Nicomedia. Diocletian had embarked on a successful series of reforms to rehabilitate the empire’s finances, military strength, and cohesion. Christians, by refusing to worship the emperor or any of the other Roman gods, were thus a political threat.

532 The foundation of Hagia Sophia is laid
In the two centuries following the persecutions of Diocletian, Christianity became the state religion of the Roman empire. The greatest church in Christendom (and the most imposing building on Earth for the next millennium) was the Church of Holy Wisdom, commissioned by the emperor Justinian to replace the one destroyed during the Nike Rebellion. Pictured above is how it would have looked before it was converted to a mosque in the 15th century and the addition of four minarets.

1455 The printing of the Gutenberg Bible
Though the Chinese had used block printing for centuries, Europe had lacked a way of mechanically reproducing books until Johann Gutenberg of Mainz invented a moveable-type press. The first fruit of his labours was a Vulgate Bible, a 5th-century Latin translation by St Jerome of the Hebrew Old Testament and the Greek New Testament. This was a moment whose revolutionary impact cannot be over-estimated.