It is hardly necessary to add that the Greek theatres were not roofed. The Romans shaded the spectators in their theatres and amphitheatres by means of a velarium or awning, but it is extremely doubtful whether even this expedient was in use in Greek theatres. _The Openings._ The most important characteristic of the openings in Greek buildings is that they were flat-topped,--covered by a lintel of stone or marble,--and never arched. We have already[17] shown that this circumstance is really of the first importance as determining the architectural character of buildings. Doors and window openings were often a little narrower at the top than the bottom, and were marked by a band of mouldings, known as the architrave, on the face of the wall, and, so to speak, framing in the opening. There was often also a small cornice over each (Figs. 82, 83). Openings were seldom advanced into prominence or employed as features in the exterior of a building; in fact, the same effects which windows produce in other styles were in Greek buildings created by the interspaces between the columns. _The Columns._ These features, together with the superstructure or entablature, which they customarily carried, were the prominent parts of Greek architecture, occupying as they did the entire height of the building. The development of the orders (which we have explained to be really decorative systems, each of which involved the use of one sort of column, though the term is constantly understood as meaning merely the column and entablature) is a very interesting subject, and illustrates the acuteness with which the Greeks selected from those models which were accessible to them, exactly what was suited to their purpose, and the skill with which they altered and refined, and almost redesigned, everything which they so selected. [Illustration: FIG. 82.--GREEK DOORWAY SHOWING CORNICE.] [Illustration: FIG. 83.--GREEK DOORWAY. FRONT VIEW. (FROM THE ERECHTHEIUM.)]