8Circular temples are also constructed, of which some are monopteral, having columns without a cell; others are called peripteral. Those without a cell have a raised floor (tribunal), and an ascent thereto equal to one third of their diameter. On the pedestals (stylobatæ) columns are raised, whose height is equal to the diameter which the pedestal occupies, and their thickness, including the bases and capitals, one tenth part of their height. The height of the architrave is half a diameter; the frieze and members over it are to be proportioned according to the directions to that effect which have been given in the third book.
2But if the building be peripteral, two steps, and then the pedestals are built thereunder; the wall of the cell is raised at a distance from the pedestals of about one fifth of the whole diameter, and in the middle is left an opening for the door. The clear diameter of the cell within the walls, is to be equal to the height of the columns above the pedestals. The columns round the cell are proportioned as above directed.
3In the centre of the roof, the height of it is equal to half the diameter of the work, exclusive of the flower. The flower without the pyramid is to equal in dimensions the capitals of the columns. The other parts are to be similar in proportions and symmetry to those already described.
4Other species of temples are also erected, regulated on the same principles, but with a different arrangement of parts, such as the temple of Castor in the Circus Flaminius, and of Beardless Jupiter (Vejovis), between the two groves. As also, though more ingeniously contrived, that of Diana Aricina, with columns on each flank of the pronaos. The first temples built similar to that of Castor in the Circus, were those of Minerva on the Acropolis of Athens, and of Pallas at Sunium in Attica, the proportions of which are similar. The length of the cells is double their breadth, and in other respects, those symmetries which are used in the fronts are preserved on the sides.
5Others, with an arrangement of columns similar to that observed in Tuscan temples, transfer it to Corinthian and Ionic designs; for in some examples, instead of the antæ which run out from the pronaos, two columns are substituted, and thus Tuscan and Greek principles are mixed.
6Others removing the walls of the cell, and placing them between the intercolumniations of the pteroma, give more space to the cell by their removal, and by preserving in other respects the same proportions and symmetry, seem to have invented another species which may be called pseudoperipteral. These different sorts of temples are dependent on the sacrifices performed in them; for temples to the gods are not all to be constructed in the same manner, the worship and sacred rites of each being different.
7I have, according to the rules taught to me, explained the different principles on which temples are constructed, the different orders and symmetry of their detail, wherein and how they respectively differ; and this I have written to the best of my ability. I shall now describe the altars of the immortal gods, and their situation as adapted to sacrifices.