In 1120, Thomas Becket was born in London; in 1170, he was murdered in his Cathedral. By the time his remains were translated (moved) to a new shrine in the cathedral, Canterbury had become a major pilgrimage destination and a place of healing. Perhaps relatively few of the healings recorded by the Benedictine custodians would be recognised as miracles today but those who were healed, whether by divine intervention or the workings of human psychology – mind over matter, if you will – went home rejoicing. Even King Henry II, whose tempestuous outburst spurred the four knights to confront and kill the Archbishop, came as a penitent pilgrim.
But in 1538 another king was angry. Henry VIII wanted a divorce from Catharine of Aragon, who had borne a daughter but no son. Unable to attack militarily the Pope who had refused the divorce, he divorced the Church of England from the Catholic church. Thomas, the low-born bishop who had stood up to the king was now, not a martyred saint but a traitor, whose name was to be forgotten, written out of history, even out of prayer books.
This Link is to a post from Magdalene College, Cambridge. It tells how this was done, using actual books in their libraries; a good read.