Both before and after the 1708 passage of the Foreign Protestants Naturalization Act, an estimated 50,000 Protestant Walloons and Huguenots fled to England, with many moving on to Ireland and elsewhere. In relative terms, this was one of the largest waves of immigration ever of a single ethnic community to Britain. Andrew Lortie (born André Lortie), a leading Huguenot theologian and writer who led the exiled community in London, became known for articulating their criticism of the Pope and the doctrine of transubstantiation during Mass.