It is probable that the first real knowledge of 'the white Christ' came, as is so often the case, with the extension of trade--Frisians trading with Scandinavia, and Danes and Swedes settling in Frisia and elsewhere for the same purpose. St Willibrord at the beginning of the 8th century and Archbishop Ebbo of Rheims in 823, as papal legate among the northern peoples, undertook missions to Denmark, but it was in 826, when king Harold was baptised at Mainz, that the first real opportunity came for the preaching of Christianity in Denmark. Harold was accompanied on his return by St Anskar, a monk from Corvey and a man filled with religious zeal. After two years' mission in Denmark St Anskar sailed to Sweden, where he was graciously received at Björkö by king Björn. He made many converts and on his return home in 831 was made archbishop of Hamburg and given, jointly with Ebbo, jurisdiction over the whole of the northern realms. Hamburg was devastated in 845 and St Anskar was then appointed to the bishopric of Bremen, afterwards united to a restored archbishopric of Hamburg. He laboured in Denmark once more and established churches at Slesvík and Ribe. He conducted a second mission to Sweden and his missionary zeal remained unabated until his death in 865; his work was carried on by his successor and biographer St Rimbert and by many others. Their preaching was however confined to Jutland and South Sweden and there is no evidence of any popular movement towards Christianity. Gorm the Old was a steadfast pagan but Gorm's son Harold Bluetooth was a zealous promoter of Christianity. His enthusiasm may have been exaggerated by monastic chroniclers in contrast to the heathenism of his son Svein, but with the accession of Cnut all fears of a reversion to heathendom were at an end. Cnut was a devout son of the Church. The first Danish settlers in England were entirely heathen in sentiment, but they were soon brought into close contact with Christianity, and the terms of the peace of Edward and Guthrum in the early years of the 10th century show that already Christianity was making its way in the Danelagh. In the course of this century both archbishoprics were held by men of Danish descent and the excesses of the early 11th century were due, not to the Danish settlers, but to the heathen followers of Olaf Tryggvason and Svein Forkbeard. Similarly the Danish settlers in Normandy were within a few years numbered among the Church's most enthusiastic supporters, and Rollo's own son and successor William was anxious to become a monk.