He played an important part in the setting up of the Council of Trent, where his voice was heard through the treatises he wrote for its guidance even though he was not well enough to attend; and wrote a further work to guide the Bishop of Córdoba in the implementation of the Council’s reforms. He spent his last years in Montilla, and there he fell asleep in the Lord on 10 May 1569.

  Antonino Fierozzi was born in Florence in 1389 and in 1405 was received into the Order of Preachers “for the future priory of Fiesole” by Blessed John Dominic, who at that time was reforming the Dominican priories of the area according to the wishes of Blessed Raymond of Capua. He served the friars in various priories in Italy, often as local superior, and became a distinguished master of canon law. In 1436 he founded the famous priory of San Marco in Florence and under his leadership Fra Angelico decorated the priory and an outstanding library was collected. His wisdom and pastoral zeal made him a natural choice for Archbishop of Florence in 1446. He was noted for his service to the poor and established a society under the patronage of Saint Martin to assist him in this work. Among his writings the best known is his Summa moralis.

  His whole life was mirrored in his last words, “to serve God is to reign.” He died on May 2, 1459.

  Didyums was a leading opponent of Arianism, which held that Christ is not truly divine but a created being. He was, however, also a follower of Origen and took on some of his errors, so that, although he was not condemned by name at the time that Origenism as a whole was condemned, his works fell out of fashion and, as they were not copied, gradually disappeared over the centuries.

  Didymus’ Trinitarian and Christological doctrine is, however, perfectly orthodox. He was a pioneer in expressing the doctrine of the Trinity in a way that was clear and unambiguous and could not be misunderstood. This was a delicate business requiring a careful choice of terms, especially in Greek, which lacked a direct equivalent of straightforward Latin words such as persona. “On the Trinity”, which is used in the Office of Readings, is his most important work.

  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.