+THE PERICLEAN AGE.+ The Persian wars may be taken as the dividing line between the Transition period and the Periclean age. The _élan_ of national enthusiasm that followed the expulsion of the invader, and the glory and wealth which accrued to Athens as the champion of all Hellas, resulted in a splendid reconstruction of the Attic monuments as well as a revival of building activity in Asia Minor. By the wise administration of Pericles and by the genius of Ictinus, Phidias, and other artists of surpassing skill, the Acropolis at Athens was crowned with a group of buildings and statues absolutely unrivalled. Chief among them was the +Parthenon+, the shrine of Athena Parthenos, which the critics of all schools have agreed in considering the most faultless in design and execution of all buildings erected by man (Figs. 31, 34, and Frontispiece). It was an octastyle peripteral temple, with seventeen columns on the side, and measured 220 by 100 feet on the top of the stylobate. It was the work of Ictinus and Callicrates, built to enshrine the noble statue of the goddess by Phidias, a standing chryselephantine figure forty feet high. It was the masterpiece of Greek architecture not only by reason of its refinements of detail, but also on account of the beauty of its sculptural adornments. The frieze about the cella wall under the pteroma ceiling, representing in low relief with masterly skill the Panathenaic procession; the sculptured groups in the metopes, and the superb assemblages of Olympic and symbolic figures of colossal size in the pediments, added their majesty to the perfection of the architecture. Here also the horizontal curvatures and other refinements are found in their highest development. Northward from it, upon the Acropolis, stood the +Erechtheum+, an excellent example of the Attic-Ionic style (Figs. 35, 36). Its singular irregularities of plan and level, and the variety of its detail, exhibit in a striking way the Greek indifference to mere formal symmetry when confronted by practical considerations. The motive in this case was the desire to include in one design several existing and venerated shrines to Attic deities and heroes--Athena Polias, Poseidon, Pandrosus, Erechtheus, Boutes, etc. Begun by unknown architects in 479 B.C., and not completed until 408 B.C., it remains in its ruin still one of the most interesting and attractive of ancient buildings. Its two colonnades of differing design, its beautiful north doorway, and the unique and noble caryatid porch or balcony on the south side are unsurpassed in delicate beauty combined with vigor of design.[11] A smaller monument of the Ionic order, the amphiprostyle temple to +Nike Apteros+--the Wingless Victory--stands on a projecting spur of the Acropolis to the southwest. It measures only 27 feet by 18 feet in plan; the cella is nearly square; the columns are sturdier than those of the Erechtheum, and the execution of the monument is admirable.