But these faults, though serious enough, do not include everything that can be said against the west front of the minster. Gothic churches have often been noble and triumphant works of art in spite of errors almost as grave. Unfortunately the west front suffers from a tendency first beginning to show itself in the middle of the fourteenth century, which afterwards became the most serious drawback of the whole Perpendicular style. It is not only because the porches do not project that it appears flat and thin. The west front of Notre Dame at Paris has no projecting porches, yet the alternations of bare spaces of wall and of rich and deep masses of carving, the strong horizontal lines, and the deep-set windows, give it a boldness and strength altogether wanting at York. Like all Norman and earlier Gothic work, it has this great merit, often most strongly felt by people who are quite unable to explain it, that the design seems to emphasise, and to be dictated by, the materials in which it is carried out. The Norman architect never forgot for a moment--he was not skilful enough to forget--that he was building with stone. So he did not conceive of his west front as a flat space to be ornamented, but as a wall to be built, and naturally his ornament followed and emphasised the main lines of his building. His single pillars, with their heavy capitals, bore witness that they were made of great stones piled one on the top of the other; his simple windows were merely openings in the wall to let in light. [Illustration: The Exterior, from the South-East.]