of the side-view and of all intermediate attitudes. This singular state of things seems to have become established in the course of the 1st century A.D. Parthian art, with its distinct use of frontality in portraiture, was lost and abandoned with the profound cultural and political changes brought by the Sasanian Empire. However, even after the Roman occupation of Dura-Europos in 165 AD, the use of Parthian frontality in portraiture continued to flourish there. This is exemplified by the early 3rd-century AD wall murals of the Dura-Europos synagogue, a temple in the same city dedicated to Palmyrene gods, and the local Mithraeum. Parthian architecture adopted elements of Achaemenid and Greek architecture, but remained distinct from the two. The style is first attested at Mithridatkert/Nisa. The Round Hall of Nisa is similar to Hellenistic palaces, but different in that it forms a circle and vault inside a square space. However, the artwork of Nisa, including marble statues and the carved scenes on ivory rhyton vessels, is unquestionably influenced by Greek art. A signature feature of Parthian architecture was the iwan, an audience hall supported by arches or barrel vaults and open on one side. Use of the barrel vault replaced the Hellenic use of columns to support roofs. Although the iwan was known during the Achaemenid period and earlier in smaller and subterranean structures, it was the Parthians who first built them on a monumental scale. The earliest Parthian iwans are found at Seleucia, built in the early 1st century AD. Monumental iwans are also commonly found in the ancient temples of Hatra and perhaps modeled on the Parthian style. The largest Parthian iwans at that site have a span of 15 m (50 ft). Clothing and apparel The typical Parthian riding outfit is exemplified by the famous bronze statue of a Parthian nobleman found at Shami, Elymais. Standing 1.9 m (6 ft), the figure wears a V-shaped jacket, a V-shaped tunic fastened in place with a belt, loose-fitting and many-folded trousers held by garters, and a diadem or band over his coiffed, bobbed hair. His outfit is commonly seen in relief images of Parthian coins by the mid-1st century BC. Examples of clothing in Parthian inspired sculptures have been found in excavations at Hatra, in northwestern Iraq. Statues erected there feature the typical Parthian shirt (qamis), combined with trousers and made with fine, ornamented materials. The aristocratic elite of Hatra