More perfect and more interesting than any of these is the Pantheon, which is undoubtedly one of the finest temples of the ancient world. Externally its effect is very much destroyed by its two parts, the circular and the rectangular, being so dissimilar in style and so incongruously joined together. The portico especially, in itself the finest which Rome exhibits, is very much injured by being prefixed to a mass which overpowers it and does not harmonise with any of its lines. The pitch, too, of its pediment is perhaps somewhat too high, but, notwithstanding all this, its sixteen columns, the shaft of each composed of a single block, and the simple grandeur of the details, render it perhaps the most satisfactory example of its class. [Illustration: 190. Plan of Pantheon at Rome. Scale 100 ft. to 1 in.] The pillars are arranged in the Etruscan fashion, as they were originally disposed in front of three-celled temples. As they now stand, however, they are added unsymmetrically to a rotunda, and in so clumsy a fashion that the two are certainly not part of the same design and do not belong to the same age. Either it was that the portico was added to the pre-existing rotunda, or that the rotunda is long subsequent to the portico. Unfortunately the two inscriptions on the portico hardly help to a solution of the difficulty. The principal one states that it was built by M. Agrippa, but the “it” may refer to the rotunda only, and may have been put there by those who in the time of Aurelius[168] repaired the temple which had “fallen into decay from age.” This hardly could, under any circumstances, be predicated of the rotunda, which shows no sign of decay during the last seventeen centuries of ill-treatment and neglect, and may last for as many more without injury to its stability, but might be said of a portico which, if of wood, as Etruscan porticoes usually were, may easily in 200 years have required repairs and rebuilding. From a more careful examination on the spot, I am convinced that the portico was added at some subsequent period to the rotunda. If by Agrippa, then the dome must belong to Republican times; if by Severus it may have been, as is generally supposed, the hall of the Baths of Agrippa.[169] Altogether I know of no building whose date and arrangements are so singular and so exceptional as this. Though it is, and always must have been, one of the most prominent buildings in Rome, and most important from its size and design, I know of no other building in Rome whose date or original destination it is so difficult to determine. [Illustration: 191. Half Elevation, half Section, of the Pantheon at Rome. Scale 50 ft. to 1 in.]