An ambulatory is a covered walkway around the central part of a building, which is usually a covered hall but may be an open court. The latin ambulatio, like the Greek peridromos, originally meant only the open space around a house. An ambulatory may be in the form of a peristyle, or colonnade (see below), such as those surrounding Greek temples or courtyards, but more often it is enclosed in walls, as in churches of the basilica plan. The inner walls may be connected with the central part of the building by one or more openings, and the outer walls may open into small chapels. An ambulatory may be carried around all four sides of the central area, or it may be U-shaped.
Ambulatories were used in temples and palaces in ancient Ur, Assur, Babylon, and Egypt. Examples in Egypt are in the grave temple of Peribsen, an early king of the Second Dynasty at Abydos (Um al-Qa‘b), and the innermost sanctuary of temples of the New Kingdom to the Roman period in Karnak.
In early Christian architecture of the sixth century under Justinian, ambulatories were incorporated in large churches on the central plan. Famous examples are the churches of San Vitale in Ravenna and Saints Sergius and Bacchus in Constantinople (Krautheimer, 1965, pp. 161-70). The East Church of Abu Mina, near Alexandria, had an ambulatory. Ambulatories were also used in Egyptian churches of the basilica plan, notably a linking of the two side aisles with the return aisle (see below) across the western end of the church, as in the churches at Pbow.
Ambulatories were used in a group of four-columned churches in the Nile Valley, some of which survived in Nubia until the completion of the Aswan High Dam in 1971 (Grossmann, 1980, pp. 85-111). Some buildings of the Fatimid period (tenth to the twelfth century) with a central plan have ambulatories, for example, DAYR AL-KUBANIYYAH.
The roofing of the corner positions in the ambulatory presented a technical problem since at these points supports were missing on one side. Therefore, to bridge the area in question, additional stone beams or auxiliary arches had to be introduced. From a spatial point of view, the corner areas were thereby always merged with one of the two sections of the ambulatory; from a constructional point of view, it did not matter which. In ancient Mesopotamian buildings, asymmetrical arrangement was preferred as in Ur and Assur (Hrouda, 1971, pp. 143-46, 155-58). In the tomb of King Peribsen at Abydos (Petrie, 1901, Vol. 2, p. 11) the merging circulates in a definite direction.
The same solution appears in the fire temple of the great Parthian sun god at Hatra in Mesopotamia (Reuther, 1938, pp. 437- 39). In other Iranian fire temples, the corner area of the ambulatory was generally completely separated off and roofed with a small cupola of its own (Reuther, 1938, pp. 550-57). In the small four-columned churches of the Nile Valley asymmetrical solution was again chosen.
Only in the vaulted buildings of the Fatimid period was a solution found that made it unnecessary to use auxiliary arches in the corner areas to carry the vaulting. In these examples, squinch arches constructed diagonally over a corner were used to serve as the support for larger arches over the remaining space. Examples of this construction have survived in the corridor vaulting of the accommodation building in DAYR ANBA HADRA, Aswan (Grossmann, 1982, pp. 245-46).
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- Grossmann, P. Elephantine, Vol. 2. Mainz, 1980.
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- Hrouda, B. Vorderasien, Vol. 1. Munich, 1971.
- Krautheimer, R. Early Christian and Byzantine Architecture. New York, 1965.
- Petrie, W. M. F. The Royal Tombs of the First Dynasty, Vol. 2. Memoirs of the Egyptian Exploration Fund 21. Oxford, 1901. Repr. 1975.
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