The fifth period extends from the last decades of the Republic to the earthquake of the year 63 A.D. In the entire period, covering more than a century, we are unable to distinguish a series of buildings which may be classed together in style and construction as constituting a homogeneous, representative group. Here and there we can point out a piece of masonry which, from its similarity to that of the fourth period, may be assigned to the end of the Republic; again, walls with reticulate facing of tufa and corners of brick-shaped blocks of the same stone belong to the time of Augustus (Fig. 12), while reticulate work with corners of brick (Fig. 95) is of later date; but there is a total lack of those distinguishing characteristics which would serve to set off by themselves all the buildings belonging to a particular time. Consequently in the case of each structure it is necessary to take into account all the circumstances, and then to form an independent judgment regarding its style and date. [Illustration: Fig. 12.--Reticulate facing, with corners of brick-shaped stone. The filled arch is probably to bear the weight of the wall over a sewer.] The difficulty is further enhanced by the fact that three styles of wall decoration fall within the limits of the same period. The Architectural Style, already mentioned, remained in vogue to the time of Augustus; it then gave place to the third or Ornate Style, which is characterized by a freer use of ornament and the introduction of designs and scenes suggestive of an Egyptian origin. The fourth or Intricate Style came in about the year 50 A.D., and represents, with its involved and fantastic designs, the last stage in the development of Pompeian wall decoration. In the fifth period marble began to be employed as a building material; the earliest dated example of its use is the temple of Fortuna Augusta, erected about 3 B.C. The sixteen years between the earthquake of 63 A.D. and the destruction of the city form the sixth period in the architectural history of Pompeii. The buildings belonging to it can be easily recognized, not only from their similarity in style and ornament, but also from certain external characteristics, as newness of appearance, unfinished condition, and the joining of new to broken walls. The only important building wholly new is the large bathing establishment, the Central Baths, at the corner of Stabian and Nola streets. For the rest, effort seems to have been directed toward restoring the ruined buildings as nearly as possible to their original condition. The wall decoration throughout is of the Intricate Style.