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 fragments induces us to suppose that the original wall did not run in straight lines, but was rather circular in form[685]. In this uncertainty I prefer to follow the indication of Quaresmius[686], who doubtless was able to see quite enough of the original building to ascertain its general plan. He says distinctly that was octagonal. 'The lower parts of the walls are left, as well as some bases of columns and foundations, from which we can infer how magnificent it was. Externally it was an octagon in form, and inside was an ambulatory, supported by one row of columns.'" From an examination of the spot I am induced to believe that Quaresmius could not have seen much more than now remains; and therefore cannot say whether he imagined or really saw the octagon. In the latter case I suppose that its ruins have perished since his time; and therefore M. de Vogüé cannot have seen the fragments of the 'wall of rubble-work connecting the piers.' I do not deny that his restoration of the church deserves careful consideration, and probably conveys a true idea of the building: but I believe that it cannot be restricted to the present dimensions, and that we can place no reliance upon the bases of columns and walls now remaining, because they have been arranged according to the caprice of the Mohammedans, as was most convenient. This I will presently explain; however, the Plan itself will shew it. The church erected by the Crusaders was destroyed by the Saracens, A.D. 1187. "Others indeed devastated the most holy Mount of Olives, where the Lord, as we read in the Gospels, was often wont to pray ... on which a church is built, on the spot where our Lord Jesus Christ was taken up into heaven on the fortieth day after His resurrection. In the middle of this a structure of wonderful roundness and beauty is erected, where the Lord placed His feet[687]."