The last of the three Scandinavian kingdoms fully to enter the Christian fold was Sweden. Christians were to be found there at least as early as the ninth century, and Anskar visited the land more than once. By 936, such Christian communities as had existed seem to have disappeared, but the faith was soon renewed. Many Swedes who had been in England as merchants or soldiers and had been baptized there returned home. In the second half of the tenth century, there were bishops in Sweden. Early in the eleventh century, a Swedish king, Olof Skotkonung, was baptized and inaugurated a bishopric under the jurisdiction of the see of Hamburg-Bremen. Although most of the land was still pagan and the main shrine of the old worship was maintained, as formerly, at Uppsala, missionaries from England were preaching the new faith. As was to be expected and as was true in Norway, Christianity triumphed first in the south, nearer to Christendom, and paganism lingered longer in the north. It was not until the first decades of the twelfth century that Christianity was dominant. Monasticism entered through the Cistercians who, as we are to see, represented a revival in that movement. When, in 1164, Sweden was given its own archiepiscopal see, its first incumbent was a Cistercian, its seat was placed at Uppsala, and the cathedral was erected on the site of the head temple of the pre-Christian pagan cult. Thus was Christianity clearly victor, and not in a lax form, but headed by a member of that order, then young, which represented one of the latest and strictest attempts to conform fully to the Christian ideal.
From: A History of Christianity: Volume 1: to AD 1500 by Kenneth Scott Latourette; 2nd edition; reprint (Peabody: Prince Press, n.d.), p. 389. This is a reprint of the 2nd edition of 1975. The first edition, in one volume, was published in 1953.
Kenneth Scott Latourette (1884-1968) taught the history of Christianity at Yale Divinity School from 1921 to 1953.