In that cylinder also on the west side a kind of door is always open, and through it those who enter can easily approach the sacred dust, and, by stretching out their hands through the aperture of the covering, can take particles of the sacred dust. On the west side of the upper part of the aforesaid rotunda are eight windows with glass lights; and the same number of lamps is suspended by cords within over against them; each being hung neither above nor below, but as it were part and parcel of the window, directly behind which it is seen. The brightness of these lamps shining through the glass is so great, that not only is the western side of Olivet adjoining the church illuminated, but also the greater part of the city of Jerusalem from the bottom of the Valley of Jehoshaphat is lighted up in the same manner." Willibald's description confirms, in every respect, that of Arculf. We do not know precisely what became of the building at the time of Hakem's persecution, A.D. 1010, but it seems probable that the Khalif destroyed a considerable part of it; because, when Sæwulf visited the place, A.D. 1103, he saw a small tower supported by columns, and surrounded by a court paved with marble. The altar was inside, placed on the rock; and there was another altar to the east in the choir a little distance from the columns, where the Patriarch celebrated mass on Ascension-Day. In the first half of the twelfth century the Crusaders rebuilt the church on this site, and added a convent occupied by Canons of the Augustinian order[680]. Their habit was white[681]. I only give the Plan of the present building, as there are not sufficient remains to enable me to reconstruct that of the Crusaders, and I but partially accept the conclusions which M. de Vogüé has drawn from the testimony of Quaresmius[682]: "The ancient church was a regular octagon in plan: all the bases of the corner pillars still remain; it is easy therefore to determine its perimeter. The octagon forming the base of the plan is inscribed in a circle 111-1/2 feet in diameter. The building has not been laid out with much accuracy, as the length of the sides of the octagon (measured on the outside) vary between 39-1/4 and 42-1/2 feet[683]. This fault proceeds from a want of exactness in the execution; since it was evidently the intention of the architects to construct a regular building, to recall by its polygonal form the ancient rotunda whose ruins it replaced. There is a similar want of regularity in the bases[684]; some are larger than others without any apparent motive.... The bases of the columns sustaining the inner rotunda have entirely disappeared; but they existed in the time of Quaresmius, who has placed them in his plan equidistant from the centre and the inside wall ... a wall of rubble-work, no doubt pierced with windows, connected the corner piers. Nothing remains of this except some shapeless fragments of its substructure. The examination of these