Diocletian's Palace - Architecture

Architecture

The ground plan of the palace is an irregular rectangle (approximately 160 meters x 190 meters) with towers projecting from the western, northern, and eastern facades. It combines qualities of a luxurious villa with those of a military camp, with its huge gates and watchtowers. The palace is enclosed by walls, and at times, it housed over 9000 people. Subterranean portions of the palace feature barrel vaulted stonework.

Only the southern facade, which rose directly from, or very near to, the sea, was unfortified. The elaborate architectural composition of the arcaded gallery on its upper floor differs from the more severe treatment of the three shore facades. A monumental gate in the middle of each of these walls led to an enclosed courtyard. The southern sea gate (the Porta Aenea) was simpler in shape and dimensions than the other three, and it is thought that it was originally intended either as the emperor's private access to the sea, or as a service entrance for supplies.

The design is derived from both villa and castrum types, and this duality is also evident in the arrangement of the interior. The transverse road (decumanus) linking the eastern gate (the Silver Gate or Porta argentea) and western gate (the Iron Gate or Porta ferrea) divided the complex into two halves. In the southern half were the more luxurious structures; that is, the emperor's apartments, both public and private, and religious buildings. The emperor's apartments formed a block along the sea front and were situated above a substructure because the sloping terrain demanded significant differences in level. Although for many centuries almost completely filled with refuse, most of the substructure is well preserved, and indicates the original shape and disposition of the rooms above.

A monumental court, called the Peristyle, formed the northern access to the imperial apartments. It also gave access to Diocletian's mausoleum on the east (now Cathedral of St. Domnius), and to three temples on the west (two of which are now lost, the third having become a baptistery, originally being the temple of Jupiter). There is a temple just to the west of the Peristylum called The Temple of the Aesculapius, which has a semi cylindrical roof made out of hand carved stone blocks which did not leak until the 1940s, and was then covered with a lead roof. The temple was restored recently.

The northern half of the palace, divided in two parts by the main north-south street (cardo) leading from the Golden Gate (Porta aurea) to the Peristyle, is less well preserved. It is usually supposed that each part was a residential complex, housing soldiers, servants, and possibly some other facilities. Both parts were apparently surrounded by streets. Leading to perimeter walls there were rectangular buildings, possibly storage magazines.

The Palace is built of white local limestone and marble of high quality, most of which was from Brač marble quarries on the island of Brač, of tuff taken from the nearby river beds, and of brick made in Salonitan and other factories. Some material for decoration was imported: Egyptian granite columns and sphinxes, fine marble for revetments and some capitals produced in workshops in the Proconnesos.