The advance of Christianity during the tenth century may be attributed to a large extent to the prevalence of the practice known as _prime-signing_ or marking with the sign of the cross. According to _Eyrbyggja Saga_ (ch. 50), this was “a common custom among merchants and mercenary soldiers in Christian armies, because those men who were ‘prime-signed’ could associate with Christians as well as heathens, while retaining that faith which they liked best.” Nearly all the Norse kings who reigned in Dublin during this century seem to have accepted Christianity. When Gothfrith plundered Armagh in 919 “he spared the church and the houses of prayer, with their company of culdees (ceile-de) and the sick.”[202] We may assume that Sihtric Gale, Gothfrith’s brother (or cousin) was also a Christian, since he formed a friendly alliance with Aethelstan, who gave him his sister in marriage.[203] In 943 Olaf Cuaran was baptized, and in the same year Rögnvaldr, another Norse prince, was confirmed.[204] After the battle of Tara (980) Olaf went on pilgrimage to Iona, where he died “after penance and a good life.”[205] His daughter and grandson were called by distinctively Irish Christian names--Maelmuire[206] (servant of Mary), and Gilla Ciarain[207] (servant of St. Ciaran). We may also note the name Gilla-Padraig which occurs in the royal family of Waterford[208] and the half-Irish name of a priest in Clonmacnois, Connmhach Ua Tomrair, who must have been of Norse extraction.[209]
But all traces of heathenism in Ireland had not disappeared by the end of the tenth century. An interesting relic was Thor’s ring (Ir. _fail Tomhair_) which was carried off from Dublin by King Maelsechnaill II. in 994.[210] This must have been the _dóm-hringr_, so frequently alluded to in Icelandic literature. It was a ring of silver or gold, about twenty ounces in weight, which lay upon an altar in the temple, except during ceremonies, when it was worn on the priest’s arm.[211] Upon this ring oaths were usually sworn.[212] That it was connected with the worship of Thor is clear from a passage in the _Landnámabók_ describing a place called Thorsnes in Iceland: “there still stands Thor’s stone, on which were broken the backs of those men who were about to be sacrificed, and close by is the _dómhringr_ where the men were condemned to death.”[213] Even as late as the year A.D. 1000 we hear of Thor’s wood (_caill Tomair_) north of Dublin, which was laid waste by Brian Borumha after the battle of Gleann Mama.[214]