The earliest Irish martyrology was compiled in prose and verse at Tallaght, near Dublin, about the year 830. Little has hitherto been known of its circulation before the period 1150-60, when the surviving copy of the prose version was made. Now, through the martyrology of the Regensburg Schottenkloster, we know that a copy of the metrical version had reached Bavaria in the southern part of Germany by the late tenth century, where it was used, first by the Irish monks of the Regensburg Schottenkloster, then as a source of entries in other local German martyrologies. The martyrology, edited here for the first time, bears witness, therefore, to the circulation in Bavaria of this originally Irish compilation and, together with other documents, shows how the Scottish Benedictine monks, who succeeded the Irish in several monasteries in southern Germany and Austria, adapted to their own use a number of essentially Irish liturgical documents.