We must, however, not accuse the original designers of the tower of this mere striving after enormous height. The uppermost stage, where the square building takes an octagonal form, is an addition of nearly two hundred years later, when the nice perceptions and exquisite taste of an earlier period were lost, and size was the goal of effort, rather than beauty. Those who built at that later time would have gone higher had they dared, but if they lacked something as artists, they must at least be credited with engineering knowledge. They knew that the mere crushing weight of stone upon stone would, if further added to, grind the lower stages into powder and so wreck the whole fabric. So, at a height of two hundred and fifteen feet, they stayed their hands; but, in earnest of what they would have done, had not prudence forbade, they crowned the topmost battlements with a tall light wooden spire, removed a century ago in one of the restorations. It was from the roof of this tower, in 1845, that Basevi, an architect interested in a restoration then in progress, fell and was killed. The octagonal upper stage of this great western tower was added in the Decorated period, about 1350, when the great central octagon, the most outstanding and peculiar feature of the Cathedral, was built. Any distant view of this vast building that commands its full length shows, in addition to the western tower, a light and fairylike lantern, like some graceful coronet, midway of the long roof-ridge, where choir and nave meet. This was built to replace the tall central tower that suddenly fell in ruins in 1332 and destroyed much of the choir. To an architect inspired far above his fellows fell the task of rebuilding. There are two works among the whole range of ancient Gothic art in these islands that stand out above and beyond the rest and proclaim the hand and brain of genius. They are the west front of Peterborough Cathedral and the octagonal lantern of Ely. We do not know who designed Peterborough's daring arcaded front, but the name of that resourceful man who built _the_ great feature of Ely has been preserved. He was Alan of Walsingham, the sacrist and sub-prior of the monastery. He did not build it in that conventional and deceitful sense we are accustomed to when we read that this or that mediæval Abbot or Bishop built one thing or another, the real meaning of the phrase being that they provided the money and were anything and everything but the architects. No: he imagined it; the idea sprang from his brain, his hands drew the plans, he made it grow and watched it to its completion.