ORIENTATION, the term in architecture given to the position of a building generally with reference to the points of the compass, and more especially (as the word implies) to that of the East. It would seem that some of the Egyptian temples were orientated in the direction of the sun or of some selected star, the exact position of which on some particular day would be an indication to the priest of the exact time of the year—a matter of great importance in an agricultural country, when the calendar was not known. The orientation of Greek temples has enabled astronomers to calculate the dates of the foundation of early temples, allowance being made for the gradual changes which in the course of centuries had taken place in the precession of the equinox. The principal front of the Greek temple always faced east; and the rays of the rising sun, passing through the great doorway of the naos, lighted up the statue at the further end, this being the only occasion on which the people who came to witness the event were able to gaze on the sculptured figure of the deity.
In early Christian architecture, in the five first basilicas built by Constantine, the apse of the church was at the west end, and the priest, standing behind the altar, faced the east; this orientation being probably derived from that of the church of the Holy Sepulchre at Jerusalem and the church at Bethlehem. Three-fourths of the early churches in Rome followed this orientation, but in many it was reversed at a later date. In Sta. Sophia, Constantinople, and all the Byzantine churches, the apse was always at the east end, and the same custom obtains in the early churches in Syria and the Coptic churches in Egypt.
In Spain, Germany and England generally the eastern orientation is generally observed, but in France and Italy there are many variations. In Scotland it was the custom to fix a pole in the ground over night, and in the morning at sunrise to note the direction taken by the shadow of the pole, which was followed when setting out the axis of the choir; if such a custom had been followed in an early church, when setting out another of later date there should be some difference in the orientation of the two, on account of the variation of the obliquity of the ecliptic in the interval, and this in some cases accounts for the change of the axial line which is found in some churches, either when the east end has been rebuilt, as was constantly the case throughout Europe, or when a nave has been added to an earlier structure. In describing churches it is usual to use the terms east, west, north and south, on the assumption that the altar is at the east end, although this may not be the real bearing of the edifice.
Indirectly also the term is sometimes used in the planning of houses and the relation of the windows of the various rooms to the sunshine and the weather—in other words, to the points of the compass; thus an eastward aspect should be provided for the morning- and dining-rooms, a south-western aspect for the drawing room, a westward for the library, and north by west for the kitchen, larder, &c. (R. P. S.)