Whenever we take up a Bible we touch Irenaeus’s work, for he played a decisive role in fixing the canon of the New Testament. It is easy for people nowadays to think of Scripture – and the New Testament in particular – as the basis of the Church, but harder to remember that it was the Church itself that had to agree, early on, about what was scriptural and what was not. Before Irenaeus, there was vague general agreement on what scripture was, but a system based on this kind of common consent was too weak. As dissensions and heresies arose, reference to scripture was the obvious way of trying to settle what the truth really was, but in the absence of an agreed canon of scripture it was all too easy to attack one’s opponent’s arguments by saying that his texts were corrupt or unscriptural; and easy, too, to do a little fine-tuning of texts on one’s own behalf. Irenaeus not only established a canon which is almost identical to our present one, but also gave reasoned arguments for each inclusion and exclusion.

  Irenaeus also wrote a major work, Against the Heresies, which in the course of denying what the Christian faith is not, effectively asserts what it is. The majority of this work was lost for many centuries and only rediscovered in a monastery on Mount Athos in 1842. Many passages from it are used 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.