It will be remembered that the tomb-house begun by Dom Duarte took the form of a vast octagon some seventy-two feet in diameter surrounded by seven apsidal chapels--one on each side except that towards the church--and by eight smaller chapels between the apses. When Matheus Fernandes began his work most of the seven surrounding chapels were finished except for their vaulting, but not all, as in two or three the outer moulding of the entrance arch is enriched by small crosses of the Order of Christ, and by armillary spheres carved in the hollow; while the whole building stood isolated and unconnected with the church. The first thing, therefore, done by Matheus was to build an entrance hall or pateo uniting the octagon with the church. Unless the walls of the Pateo be older than Dom Manoel's time it is impossible now to tell how Huguet, Dom Duarte's architect, meant to connect the two, perhaps by a low passage running eastwards from the central apse, perhaps not at all. The plan carried out by Matheus took the form of a rectangular hall enclosing the central apse and the two smaller apses to the north and south, but leaving--now at any rate--a space between it and the side apses. Possibly the original intention may have been to pull down the two side apses, and so to form a square ambulatory behind the high altar leading to the great octagon beyond; but if that were the intention it was never carried out, and now the only entrance is through an insignificant pointed door on the north side. The walls of the Pateo with their buttresses, string courses and parapet are so exactly like the older work as to suggest that they may really date from the time of Dom Duarte, and that all that Matheus Fernandes did was to build the vault, insert the windows, and form the splendid entrance to the octagon; but in any case the building was well advanced if not finished in 1509, when over the small entrance door was written, 'Perfectum fuit anno Domini 1509.' Two windows light the Pateo, one looking north and one south. They are both alike, and both are thoroughly Manoelino in style. They are of two lights, with well-moulded jambs, and half-octagonal heads. The drip-mould, instead or merely surrounding the half octagon, is so broken and bent as to project across it at four points, being indeed shaped like half a square with a semicircle on the one complete side, and two quarter circles on the half sides, all enriched by many a small cusp and leaf. The mullion is made of two branches twisting upwards, and the whole window head is filled with curving boughs and leaves forming a most curious piece of naturalistic tracery, to be compared with the tracery of some of the openings in the Claustro Real. (Fig. 58.)