The Christmas festival was duly observed by the missionaries who came to the South of England from Rome, headed by Augustine, and in the northern parts of the country the Christian festivities were revived by the Celtic missionaries from Iona, under Aidan, the famous Columbian monk. At least half of England was covered by the Columbian monks, whose great foundation upon the rocky island of Iona, in the Hebrides, was the source of Christianity to Scotland. The ritual of the Celtic differed from that of the Romish missionaries, and caused confusion, till at the Synod of Whitby (664) the Northumbrian Kingdom adopted the Roman usages, and England obtained ecclesiastical unity as a branch of the Church of Rome. Thus unity in the Church preceded by several centuries unity in the State. [Illustration: QUEEN BERTHA.] In connection with Augustine's mission to England, a memorable story (recorded in Green's "History of the English People") tells how, when but a young Roman deacon, Gregory had noted the white bodies, the fair faces, the golden hair of some youths who stood bound in the market-place of Rome. "From what country do these slaves come?" he asked the traders who brought them. "They are English, Angles!" the slave-dealers answered. The deacon's pity veiled itself in poetic humour. "Not Angles, but Angels," he said, "with faces so angel-like! From what country come they?" "They come," said the merchants, "from Deira." "De ira!" was the untranslatable reply; "aye, plucked from God's ire, and called to Christ's mercy! And what is the name of their king?" "AElla," they told him, and Gregory seized on the words as of good omen. "Alleluia shall be sung in AElla's land!" he cried, and passed on, musing how the angel-faces should be brought to sing it. Only three or four years had gone by when the deacon had become Bishop of Rome, and the marriage of Bertha, daughter of the Frankish king, Charibert of Paris, with AEthelberht, King of Kent, gave him the opening he sought; for Bertha, like her Frankish kinsfolk, was a Christian.