The first of the Anglo-Saxon or English kingdoms (to give them the more generally accepted title) to acquire a definite superiority was that of Kent; but it soon gave way to the rising power of Northumbria. Nevertheless, the period of Kentish ascendency is one of great importance, for it witnessed the conversion of England to Christianity. Ethelbert, who reigned from 560 to 616, was the first prominent English king after the various sovereignties had taken shape and consistency. He married a Christian princess, Bertha, the daughter of Charibert, king of the Franks. But although she was allowed to exercise her religion, it does not appear that the new faith made any sensible progress until, in the year 597, Pope Gregory the Great determined to send a monk, named Augustine, to preach the Gospel in the land of the heathen English. The beautiful story of the means by which Gregory's attention was called to this distant land is well known. Before he became Pope, it chanced one day that he was walking in the market-place at Rome and saw some fair boys exposed for sale as slaves. His curiosity aroused, he asked of what nation they came. "They are _Angles_," was the reply. "_Non Angli sed Angeli_" ("They are not Angles, but angels"), said Gregory, "and should be the co-heirs of the angels in heaven. But of what tribe are they?" "Of Deira." "Then must they be delivered _de ira Dei_ (from the wrath of God). And who is their king?" "Ella," was the answer. "Then," said Gregory, "shall _Alleluia_ be sung in his land." When Gregory became Pope he was not long in making good the promise, as far as in him lay. Augustine's task was easy; Ethelbert permitted him and his comrades to dwell at Canterbury and preach to the people. After a while he went back to the Continent to be consecrated bishop; and on his return, made the church at Canterbury the cathedral of his diocese, whence Canterbury is still the metropolitan see of all England. Although Christianity had been exterminated by the invaders, its dying embers were rekindled among the Welsh by missionaries from the Continent, and an attempt was now made to agree upon a basis of union for the two churches. For this purpose a meeting was arranged between Augustine and the Welsh bishops at a spot on the banks of the Severn, and a conference was held. But although the points of difference were slight, neither side would yield; and so the two churches remained separate.