As a boy, Damasus had heard the story of these martyrs from their executioner. Marcellinus was a priest, Peter was not. They were beheaded during the emperor Diocletian’s persecution, and buried on the Via Labicana outside Rome.

  After the persecutions, a basilica was built over the site of their tomb.

  Pothinus was the first bishop of Lyon, and thus the first Bishop in Gaul, and was arrested in 177 during the reign of Marcus Aurelius, together with Blandina and forty-five other Christians. Pothinus is known to have been very old: the letter says 90 years old.

  Many of the martyrs died in prison or were beheaded, as befitted Roman citizens, but six of them were sentenced to be thrown to the wild beasts in the arena, among them Blandina, a slave.

  The beasts did not touch Blandina, so she was beaten, then burned, then tossed on the horns of a bull, and finally, after having witnessed the martyrdom of her companions (calmly except in the case of her friend Ponticus, whose faith and perseverance she had doubted) was strangled by the public executioner.

  Pothinus was succeeded as bishop by St Irenaeus, one of the great Fathers of the early Church.

  The matters in dispute with the Arians were vital to the very nature of Christianity; and, as Cardinal Newman put it, the trouble was that at that time the laity tended to be champions of orthodoxy while their bishops (seduced by closeness to imperial power) tended not to be. The further trouble (adds Henry Chadwick) is that the whole thing became tangled up with matters of power, organization and authority, and with cultural differences between East and West. Athanasius was accused of treason and murder, embezzlement and sacrilege. In the fight against him, any weapon would do.

  Arianism taught that the Son was created by the Father and in no way equal to him. This was in many ways a “purer” and more “spiritual” approach to religion, since it did not force God to undergo the undignified experience of being made of meat. Islam is essentially Arian. But Arianism leaves an infinite gap between God and man, and ultimately destroys the Gospel, leaving it either as a fake or as a cruel parody. Only by being orthodox and insisting on the identity of the natures of the Father and the Son and the Spirit can we truly understand the goodness of creation and the love of God, and live according to them. For this reason many extracts from the works of St Athanasius have been adopted as Second Readings in the Office of Readings.

  In the earliest centuries all vestments were white – the white of baptismal purity and of the robes worn by the armies of the redeemed in the Apocalypse, washed white in the blood of the Lamb. As the Church grew secure enough to be able to plan her liturgy, she began to use colour so that our sense of sight could deepen our experience of the mysteries of salvation, just as incense recruits our sense of smell and music that of hearing. Over the centuries various schemes of colour for feasts and seasons were worked out, and it is only as late as the 19th century that they were harmonized into their present form.