Technically known as Liber Ar(d)machanus, celebrated Irish-Latin manuscript, preserved at Trinity College, Dublin. It is a vellum in small quarto of 221 leaves, written in the Irish hand with fine penmanship. It was known as the Canon of Patrick, but was discovered to be really the work of Ferdomnach of Armagh (died c.845).The earliest extant specimen of a continuous narrative in Irish prose, it contains valuable writings relating to Saint Patrick.