A Propylaea, Propylea or Propylaia (Προπύλαια) is any monumental gateway based on the original Propylaea that serves as the entrance to the Acropolis in Athens. The word propylaea ( propylaeum is the Latin version) is the union of the prefix pro (before or in front of) plus the plural of the Greek pylon or pylaion (gate), meaning literally that which is before the gates, but the word has come to mean simply gate building. The Brandenburg Gate of Berlin and the Propylaea in Munich are specifically copied from the central portion of the Propylaea.
The monumental gateway to the Acropolis, the Propylaea was built under the general direction of the Athenian leader Pericles, but Phidias was given the responsibility for planning the rebuilding the Acropolis as a whole at the conclusion of the Persian Wars. According to Plutarch, the Propylaea was designed by the architect Mnesicles, but we know nothing more about him. Construction began in 437 BCE and was terminated in 432, when the building was still unfinished. The Propylaea was constructed of white Pentelic marble and gray Eleusinian marble or limestone, which was used only for accents. Structural iron was also used, though William Bell Dinsmoor analyzed the structure and concluded that the iron weakened the building.
The structure consists of a central building with two adjoining wings on the west (outer) side, one to the north and one to the south. The core is the central building, which presents a standard six-columned Doric façade both on the West to those entering the Acropolis and on the east to those departing. The columns echo the proportions (not the size) of the columns of the Parthenon. There is no surviving evidence for sculpture in the pediments. The central building contains the gate wall, about two-thirds of the way through it. There are five gates in the wall, one for the central passageway, which was not paved and lay along the natural level of the ground, and two on either side at the level of the building's eastern porch, five steps up from the level of the western porch. The central passageway was the culmination of the Sacred Way, which led to the Acropolis from Eleusis.
Entrance into the Acropolis was controlled by the Propylaea. Though it was not built as a fortified structure, it was important that people not ritually clean be denied access to the sanctuary. In addition, runaway slaves and other miscreants could not be permitted into the sanctuary where they could claim the protection of the gods. The state treasury was also kept on the Acropolis, making its security important.
Today the Propylaea has been partly restored, since 1984 under the direction of Dr. Tasos Tanoulas, and serves as the main entrance to the Acropolis for the many thousands of tourists who visit the area every year. In the period before the 2004 Olympic Games in Athens, the Propylaea was shrouded in scaffolding as restoration work was undertaken. At the end of 2009 all scaffolding was removed, and the building is now open fully to view again. The famous ceilings have even been partly restored.