Without actually amalgamating, the Danes seem to have drawn gradually closer to the native Irish. A royal heir of Ulster received the name of Ragnal less than half a century after Clontarf, and in 1121 a bishop seems to have been temporarily appointed at Dublin by the joint election of Irish and Danes. But quarrels were frequent even after the Danes had become fully Christianised; and when the men of Munster invaded Fingal in 1133, they burned the church of Lusk when it was full of people and treasures. Nor did fresh invasions quite cease, for Magnus, King of Norway, made two expeditions to Ireland, in the latter of which, in 1103, he lost his life. The separate history of the Irish Ostmen was drawing to a close, even at the date of the Anglo-Norman invasion; but they have left indelible traces upon the map of Ireland and on the traditional lore of her people. [Sidenote: The Danes were traders.] Giraldus informs us that the Scandinavians who settled at Dublin, Waterford, and Limerick, came under pretence of peaceful trading. The Irish, he says, were prevented by their innate sloth from going down to the sea in ships, but were ready to welcome those who would trade for them, and thus allowed the fierce strangers to get a strong footing. However this may be, it is certain that the Irish are deficient in maritime enterprise, and equally certain that the Northmen had a constant eye to trade as well as to war and plunder. Unerring instinct pointed out the best stations, and on the sites thus chosen the chief cities of Ireland were reared. The Kaupmannaeyjar or merchant isles, probably those now called the Copelands, may have been a rendezvous for passing vessels. Arabic coins, of which more than 20,000 pieces from more than 1,000 different dies are preserved at Stockholm, have been found in Ireland, and the Irish Northmen certainly had a coinage of their own, when the native princes had none. Pieces have been found which were struck by, or at least for, a Scandinavian king of Dublin as early as the ninth century, and all coins minted in Ireland up to the Anglo-Norman invasion were perhaps of similar origin. Many such pieces have been found in the Isle of Man, and some as far off as Denmark.[24] [Sidenote: They were superior to the Irish in peaceful arts.]