This contribution discusses Na all fod un Ffydd onyd yr Hen Ffydd, the earliest surviving text of the sixteenth-century Welsh author and priest Robert Gwyn, and its relationship to an earlier Welsh-language catechism titled Athravaeth Gristnogawl published by Morris Clynnog, bishop-elect of Bangor. Both texts were written for the use of Welsh-speaking Catholics living under Protestant persecution, but the authors’ views on what material that community needed were very different, leading to the production of two superficially similar, but in reality very different texts. This essay discusses the extent to which Gwyn’s composition was influenced by what he saw as flaws in Clynnog’s earlier work which left it unsuitable for use under the conditions that prevailed in Wales at the time. It compares and contrasts their methodology, both in terms of the contents of their volumes, and of the style and type of language in which they were written.