 These ideas were expanded during the English Reformation, as Protestant authors appropriated the concept of a "Celtic Church" as a native, anti-Roman predecessor to their own movement.In the 18th and 19th centuries, antiquarianism, the Romantic movement, and growing nationalism influenced ideas about what was becoming known as "Celtic Christianity".Beginning in the early 20th century, a full-fledged revival movement began, centred on the island of Iona and influenced by the Irish Literary Revival and more general Christian revivals.