A colonnade is a row of columns relatively closely spaced, usually in a straight line connected by an architrave or arches. It is a characteristic element of basilica construction. A colonnade is the same as a portico. Sequences of round columns alternating with square-sided pillars in a distinct rhythm do not count as colonnades.
If a colonnade forms a connection between two parallel walls, the columns closest to the walls are generally treated as engaged columns or pillars, that is, attached to the respective walls. In the architecture of Egypt, however, classical arrangement was generally abandoned in the pharaonic period, and instead imposts were positioned high on the wall to carry the architrave or arches.
In classical architecture down to the fourth century A.D., only uniform columns were normally used within a colonnade. A rare exception is formed by the courtyard porticoes of the Temple of Isis at Philae, belonging to the second century A.D., which in part contain different types of columns. From the fifth century A.D., probably as a result of the frequent use of elements stolen from earlier buildings, people began to accept columns of very different types into one colonnade.
Down to the sixth century, however, care was taken in church building to place columns of different kinds together in matching pairs, a practice later abandoned (Deichmann, 1940, pp. 114-30). The introduction of the vault and especially of the dome (see below), divided the space beneath into individual bays, supported by widely separated columns. Thus as the character of a closed sequence was lost, the colonnade fell out of use.
- Deichmann, F. W. “Säule und Ordnung in der frühchristlichen Architektur.” Mitteilungen des deutschen archäologischen Instituts—Römische Abteilung 55 (1940):114-30.
- Orlandos, A. K. Basilik». pp. 351-56. Athens, 1952.