Theobald Stapleton was born in Co. Kilkenny, Ireland, but was English by descent, though not connected with the Yorkshire Stapletons. Nothing is known of his career, except that he was a priest living in Flanders, and that in 1639 he published at Brussels a book called "Catechismus seu doctrina christiana latino-hibernica", which was the first book in which Irish was printed in Roman type. His object in publishing it was to promote the use of Irish in religious literature, and to further this object he added to the book an appendix in nineteen sections giving directions for reading Irish.
MEEHAN, Rise and Fall of the Irish Franciscan Monasteries (Dublin, 1870); MOORE in Dict. Nat. Biog., s.v.