The most beautiful application of Grecian architecture was in the temples, which were very numerous, and of extraordinary grandeur, long before the Persian war. Their entrance was always to the west or the east. They were built either in an oblong or round form, and were mostly adorned with columns. Those of an oblong form had columns either in the front alone, in the fore and back fronts, or on all the four sides. They generally had porticoes attached to them. They had no windows, receiving their light from the door or from above. The friezes were adorned with various sculptures, as were sometimes the pediments, and no expense was spared upon them. The most important part of the temple was the cella, where the statue of the deity was kept, and was generally surrounded with a balustrade. Beside the cella was the vestibule, and a chamber in the rear or back front in which the treasures of the temple were kept. Names were applied to the temples, as well as the porticoes, according to the number of columns in the portico at either end of the temple, such as the tetrastyle with four columns in front, or hexastyle when there were six. There were never more than ten columns in front. The Parthenon had eight, but six was the usual number. It was the rule to have twice as many columns along the sides as in front, and one more. Some of the temples had double rows of columns on all sides, like that of Diana at Ephesus, and of Quirinus at Rome. The distance between the columns varied from a diameter and half of a column to four diameters. About five eighths of a Doric temple were occupied by the cella, and three eighths by the portico. [Sidenote: Simplicity of Grecian temples.] That which gives so much simplicity and harmony in the Greek temples, which are the great elements of beauty in architecture, is the simple outline, in parallelogrammic and pyramidal forms, in which the lines are straight and uninterrupted through their entire length. This simplicity and harmony are more apparent in the Doric than in any of the other orders, and pertain to all the temples of which we have knowledge. Nor can any improvement be made upon them, or any alteration which does not conflict with established principles. The Ionic and Corinthian, or the Voluted and Foliated orders, do not possess that harmony which pervades the Doric, but the more beautiful compositions are so consummate that they will ever be taken as models of study. [Sidenote: Matchless proportions of the Grecian temples.]