Many causes, however, combined to sweep away not only all traces of these earliest churches, but also in many instances more than one more solidly constructed successor. The growth of architectural taste and skill made men impatient of the rudeness of their forefathers' simple fanes; in a surprising number of instances the lightning-flash or the raging fire destroyed the buildings wholly or in part. The cathedrals of the north felt more than once the shock of the Border wars; and civil strife, or religious fanaticism, wrought mischief in many others. Thus it has come to pass that the centuries have seen four cathedrals in succession at Hereford, at Gloucester, and at Bangor; and three at a multitude of places, Canterbury, London, Winchester, Peterborough, Lichfield, Oxford, and half-a-dozen more. The incursions of the Danes were answerable for the destruction of several of the earlier foundations. Canterbury had a cathedral, the most ancient part of which had been erected, according to tradition, by Lucius, the first Christian King of the Britons, and afterwards restored by S. Augustine. To this, about the year 740, Cuthbert, the archbishop, added a chapel for the interment of the occupants of the see; and Odo, in the tenth century, enlarged and re-roofed it. But in the days of saintly Alphege, in 1005, the Danish invaders fell upon the city, making of the church a ruin, and of its bishop a martyr. A similar fate befell the metropolitan church of the north. On the site where Paulinus baptized King Edwin and his two sons into the Christian faith a little wooden oratory was raised, over which ere long Edwin commenced to build a stone church, which S. Oswald, his successor, completed. This, after having been beautified by S. Wilfred, was burnt about 741, but re-built shortly afterwards by Archbishop Egbert. It was this latter building which fell before the Danes. At Ely the religious house founded by S. Etheldreda, which was the precursor of the modern cathedral, was burnt by the same marauders about 870. Rochester suffered in the same way; and no trace of the church built, so says the Venerable Bede, by King Ethelbert himself now remains. Peterborough has been particularly unfortunate in this respect. The first building here was begun by Peada, King of Mercia, in the seventh century. In the year 870 the Danes, on one of their forays, burnt church and monastery to the ground, and massacred the abbot and all his monks. In 971 King Edgar raised the place once more from its desolation, but again it was seriously damaged, though not absolutely destroyed, by the sea-kings shortly before the Norman Conquest. Oxford was partially burnt in 1002 owing to the same people, but in a different way. A number of Danes took refuge in the tower of S. Frideswide to escape the senseless and brutal massacre organised on S. Brice's day in that year, and the English fired the structure rather than suffer their prey to escape them.