§ 1. If the windows and doors of some of our best Northern Gothic buildings were built up, and the ornament of their archivolts concealed, there would often remain little but masses of dead wall and unsightly buttress; the whole vitality of the building consisting in the graceful proportions or rich mouldings of its apertures. It is not so in the South, where, frequently, the aperture is a mere dark spot on the variegated wall; but there the column, with its horizontal or curved architrave, assumes an importance of another kind, equally dependent upon the methods of lintel and archivolt decoration. These, though in their richness of minor variety they defy all exemplification, may be very broadly generalised.

Of the mere lintel, indeed, there is no specific decoration, nor can be; it has no organism to direct its ornament, and therefore may receive any kind and degree of ornament, according to its position. In a Greek temple, it has meagre horizontal lines; in a Romanesque church, it becomes a row of upright niches, with an apostle in each; and may become anything else at the architect's will. But the arch head has a natural organism, which separates its ornament into distinct families, broadly definable.