Achaemenid palaces had enormous hypostyle halls called apadana, which were supported inside by several rows of columns. The Throne Hall or “Hall of a Hundred Columns” at Persepolis, measuring 70 x 70 metres was built by the Achaemenid king Artaxerxes I. The Apadana hall is even larger. These often included a throne for the king and were used for grand ceremonial assemblies; the largest at Persepolis and Susa could fit ten thousand people at a time.
The Achaemenids had little experience of stone architecture, but were able to import artists and craftsmen from around their empire to develop a hybrid imperial style drawing on influences from Mesopotamia, Egypt and Lydia in Anatolia, as well as Elam in Persia itself. The style was probably developed in the Palace of Darius in Susa, but the most numerous and complete survivals are at Persepolis, where several columns remain standing. Imperial building in the style stopped abruptly with the invasion by Alexander the Great in 330 BCE, when Persepolis was burned down.
The forms of the columns and capitals vary somewhat between different buildings. Generally the capitals are carved with two heavily decorated back-to-back animals projecting out from the column. These function as brackets to support the architrave or roof timbers, while the flat backs of the animals support timbers running at right angles (see the reconstruction in the Louvre below). As they project the animals may be called protomes. The bull is the most common animal, but there are also lions, bulls with the head of a man in the style of the Assyrian lamassu, and griffins with the heads of eagles and the bodies of lions.
The bulls and lions may reflect the symbolism around Nowruz, the Persian New Year at the spring equinox, of an eternally fighting bull personifying the moon, and a lion personifying the Sun. This was the day when tributary nations presented their annual tribute to the king, as depicted in the stairway reliefs at Persepolis, and it has been suggested that Persepolis was specifically built for Nowruz celebrations.
The capital is much longer than in most other styles of columns. While some smaller columns move quickly from the animals to the plain shaft below, the largest and grandest examples have a long intervening section with double volutes at the top and, inverted, at the bottom of a long fluted square zone, although the shaft of the column is round. At the top of the round fluted shaft are two sections with a loosely plant-based design, the upper a form of “palm capital”, spreading as it rises, and the lower suggesting leaves drooping downwards. Other capitals have the animals and the two lower plant-based elements, but not the section in between with the volutes; the example in Chicago is of this type. There are various small mouldings between the various elements, reflecting a Greek style. The horns and ears of the animals are often separate pieces, fitting into the head by square plugs. The columns were polished and at least the capitals were painted, in the case of wooden ones on a plaster coating. The style reflects influences from the many cultures that the Persian Empire conquered including Egypt, Babylon, and Lydia, as well as Greece, where the Persians had only temporary success; the final result is distinctively Persian.
It is thought the stone columns that survive were preceded by wooden versions, and these continued to be used. The move to stone may have come when sufficiently large trees for the biggest buildings became difficult or impossible to source. The column shafts can be as tall as 20 metres. The base is in stone even for wooden columns, and sometimes carries an inscription saying which king erected the building. Most are round, but an early square type has two steps.