One of the masterpieces of classical architecture. This imposing entrance was designed by the architect Mnesicles and built in 437-432 BC over an earlier propylaea. Mnesicles designed an entrance no less magnificent than that of the temples and other monuments on the Sacred Rock. The Propylaea consists of a main hall and two side wings. The north wing was to house a display of paintings and was named Pinakotheke (Gallery). The outer columns to both east and west are of the Doric order; the internal entrance way is flanked by two high inner colonnades of the Ionic order. The brilliant idea of combining the Doric and Ionic orders lifts the emotions those who enter the Propylaea, giving them a rare aesthetic experience. In the 12th century, the Propylaea became the residence of the Metropolitan Michael Choniatis. During Frankish rule, the whole structure was used as a palace. Additions by the Franks included an extra floor and a high watchtower that was demolished in 1874.