The spread of the gospel towards the northern extremities of Europe, during the ninth and tenth centuries has been so fully detailed in the general histories, that we shall do little more than name the principal places, and the chief actors, in connection with the good work. But we rejoice to trace the footsteps of those self-denying missionaries, in the very heart of Satan's kingdom, where for centuries he had reigned undisturbed. We have already seen that the sword of Charlemagne had opened the way to the Frieslanders, Saxons, Huns, and other tribes.
In the early part of the reign of his son Louis, the gospel was introduced among the Danes and Swedes. Disputes, as to the throne of Denmark, between Harold and Godfrid, led Harold to seek protection from Louis. The pious Emperor thought this might be a convenient opportunity for the introduction of Christianity among the Danes. He therefore promised Harold assistance, on condition that he would embrace Christianity himself and admit preachers of the gospel into his country. The king accepted the terms, and was baptized at Mentz, A.D. 826, together with his queen and a numerous train of attendants. Louis was sponsor for Harold, the empress for his queen, Lothaire for his son; and sponsors of suitable rank were found for the members of his train. Thus Christianized, as was thought in those days, he returned home, taking two teachers of Christianity with him. And lest Harold might not regain his kingdom, Louis assigned to him an estate in Friesland.
Ansgarius and Auberg, the two French monks that accompanied them, labored with great zeal and success; but Aubert, a monk of noble birth, died in two years, amidst the toils of the missionary.
The indefatigable Ansgarius, on the death of his fellow-laborer, went over to Sweden. He was equally happy and successful in his work there. In 831 Louis rewarded his great labors by making him archbishop of Hamburg, and of all the north. He had often great opposition to encounter, but he usually disarmed his persecutors by the goodness of his intentions and the uprightness of his conduct. He lived till the year 865, and labored chiefly among the Danes, the Cimbrians, and the Swedes.