It was not till the invasion of the country by the armies of Otto I. in 938 that Christianity was restored even to full toleration, and only when Otto came himself in 950 that it was secured. Boleslav II., the nephew of S. Wenceslas, was named the Pious; and Prague, in 973, was separated from Regensburg and became a bishopric. While among the Moravians the Slavonic rite introduced by Methodius was still largely used, in Bohemia the Roman rite was followed. Voytech (Adalbert), a Czech, was the second bishop, and to him, in spite of failures and difficulties, the conversion of Bohemia was largely due. He died a martyr (as we have said), while preaching to the heathen Prussians, and for a time darkness again settled over the history of the Czechs. [Sidenote: The conversion of the Danes] Meanwhile the current of conversion had spread northwards. It was in 822 that Ebbo, Archbishop of Rheims, was sent to Denmark in consequence of a political embassy to Louis the Pious, emperor from 814 to 840. Harold, the Danish king, had asked aid. The emperor gave him also a Christian teacher; and in 826 the king and his wife were baptized. Other missionaries went northwards, but before long the Danes drove out both their king Harold and his teacher Ansgar. From Denmark, however, the mission spread to Sweden, and in 831 an archbishopric was established at Hamburg to direct all the northern {130} missions, and Ansgar was invested with the pallium by Pope Gregory IV. The missions had a chequered career. [Sidenote: and of Sweden.] Hamburg was seized and pillaged by the Northmen in 845, and the Swedish mission was for a time destroyed. In 849 a new revival took place, when Ansgar was given the see of Bremen in addition to that of Hamburg; and before long he won over the king of the Jutes and his people of Schleswig. In 853 Ansgar returned to Sweden, where he was favourably received by the king Olaf. The tale of his vast missionary labours, from which he was rightly called the "Apostle of the north," is told with spirit and feeling by Adam of Bremen, who wrote in the eleventh century, as well as by the biographer who commemorated him on his death. He not only preached, but he "redeemed captives, nourished those who were in tribulation, taught his household. As an apostle without, a monk within, he was never idle." When it was said that his prayers wrought miracles of healing, he said, "If I could but think myself worthy of such a favour from the Lord, I would pray Him to grant me but one miracle--that out of me, by His grace; He would make a good man." [Sidenote: S. Ansgar.] S. Ansgar is, in his work as in his training, a parallel to S. Boniface. Like him one of the finest fruits of monasticism, which first taught in solitude and then sent out to work actively in the world, he was brought up at Corbie. For nearly thirty-five years he laboured incessantly among the peoples of the north, and at the very end of his life he gallantly went among heathen