Here is what the official Roman Martyrology has to say:

  Thursday after Pentecost: The Feast of Our Lord Jesus Christ, The Eternal High Priest, according to the order of Melchizedek.

  In him the Father has been well pleased from before all time. As Mediator between God and human beings, fulfilling his Father’s will, he sacrificed himself once on the altar of the Cross as a saving Victim for the whole world. Thus, instituting the pattern of an everlasting sacrifice, with a brother’s kindness he chose, from among the children of Adam, men to augment the priesthood, so that, from the sacrifice continually renewed in the Church, streams of divine power might flow, whereby a new heaven and a new earth might be made, and throughout the whole universe there would be perfected what no eye has seen, nor ear heard, nor has entered into the human heart.

  When Clovis died in 511, and especially after her son Clodomir died in 524, Clotilde devoted herself to works of charity and founded many churches and religious institutions, setting a pattern that was later followed by many royal widows in Europe. She herself died by the tomb of St Martin of Tours in 545.

  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.