So recently I was in Cambridge and I happened to see a memorial to the Catholic martyrs of the university who were killed during and after the Reformation. The dates given were 1535-1678; I presume the latter was simply the year of the execution of the last Cambridge martyr, since Catholicism remained illegal for over a century afterwards. But it did get me wondering whether there would be a way to make 1678 the year in which the Church of England reunified with the Catholic Church, no earlier and no later?