Under the new primate, however, an unexpected opening occurred for the conversion of the North. The Northumbrian kings had now risen to the first place in Britain. Æthelfrith had done much to establish their supremacy; under Eadwine it rose to a height of acknowledged over-lordship. "As an earnest of this king's future conversion and translation to the kingdom of heaven," says Bæda, with pardonable Northumbrian patriotic pride, "even his temporal power was allowed to increase greatly, so that he did what no Englishman had done before–that is to say, he united under his own over-lordship all the provinces of Britain, whether inhabited by English or by Welsh." Eadwine now took in marriage Æthelburh, daughter of Æthelberht, and sister of the reigning Kentish king. Justus seized the opportunity to introduce the Church into Northumbria. He ordained one Paulinus as bishop, to accompany the Christian lady, to watch over her faith, and if possible to convert her husband and his people. Gregory had planned his scheme with systematic completeness; he had decided that there should be two metropolitan provinces, of York and London (which he knew as the old Roman capitals of Britain), and that each should consist of twelve episcopal sees. Paulinus now went to York in furtherance of this comprehensive but abortive scheme. A miraculous escape from assassination, or what was reputed one, gave the Roman monk a hold over Eadwine's mind; but the king decided to put off his conversion till he had tried the efficacy of the new faith by a practical appeal. He went on an expedition against the treacherous king of the West Saxons, who had endeavoured to assassinate him, and determined to abide by the result. Having overthrown his enemy with great slaughter, he returned to his royal city of Coningsborough (the king's town), and put himself as a catechumen under the care of Paulinus. The pope himself was induced to interest himself in so promising a convert; and he wrote a couple of briefs to Eadwine and his queen. These letters, the originals of which were carefully preserved at Rome, are copied out in full by Bæda. No doubt, the honour of receiving such an epistle from the pontiff of the Eternal City was not without its effect upon the semi-barbaric mind of Eadwine, who seems in some respects to have inherited the old Roman traditions of Eboracum.