The outside is very plain: Ionic pilasters at the angles support a simple cornice which runs round the whole building; the west end and transepts have pediments with small semicircular windows. The tile roofs are surmounted by a low square tower crowned by a flat plastered dome at the crossing and by the domed stair turret at the south-east corner. The west door is plain with a simple architrave. The square-headed windows have a deep splay--the wall being very thick--their architraves as well as their cornices and pediments rest on small brackets set not at right angles with the wall, but crooked so as to give an appearance of false perspective. The inside is very much more pleasing, indeed it is one of the most beautiful interiors to be found anywhere. (Fig. 88.) On each side of the central aisle there are three Corinthian columns, with very correct proportions, and exquisite capitals, beautifully carved if not quite orthodox. Corresponding pilasters stand against the walls, as well as at the entrance to the choir, and at the beginning of the apse. These and the columns support a beautifully modelled entablature, enriched only with a dentil course. Central aisle, transepts and choir are all roofed with a larger and the side aisles with a smaller barrel vault, divided into bays by shallow arches. In choir and transepts the vault is coffered, but in the nave each bay is ornamented with three sets of four square panels, set in the shape of a cross, each panel having in it another panel set diagonally to form a diamond. At the crossing, which is crowned by a square coffered dome, the spandrils are filled with curious winged heads, while the semi-dome of the apse is covered with narrow ribs. The windows are exactly like those outside, but the west door has over it a very refined though plain pediment. So far, beyond the great refinement of the details, there has been nothing very characteristic of João de Castilho, but when we find that the pilasters of the choir and apse, as well as the choir and transept arches, are panelled in that very curious way--with strips crossing each other at long intervals to form diamonds--which João employed in the passage arches in the Thomar dormitory and in the loggia at Batalha, it would be natural enough to conclude that this chapel is his work, and indeed the best example of what he could do with classic details. Now under the west window of the north aisle there is a small tablet with the following inscription in Portuguese[154]:--'This chapel was erected in A.D. 1572, but profaned in 1810 was restored in 1848 by L. L. d'Abreu,' etc.