J.R.R. Tolkien: The Pope and the One True Church
“I myself am convinced by the Petrine claims, nor looking around the world does there seem much doubt which (if Christianity is true) is the True Church, the temple of the Spirit dying but living, corrupt but holy, self-reforming and re-arising.
“But for me that Church of which the Pope is the acknowledged head on earth has as chief claim that it is the one that has (and still does) ever defended the Blessed Sacrament, and given it most honour, and put (as Christ plainly intended) in the prime place.
“’Feed my sheep’ was His last charge to St. Peter; and since His words are always first to be understood literally, I suppose them to refer primarily to the Bread of Life. It was against this that the W. European revolt (or Reformation) was really launched—’the blasphemous fable of the Mass’—and faith/works a mere red herring.”
Can be found in Tolkien: Man and Myth, p. 193