Some form of screen or fence, which surrounds and divides the living space, is one of the most basic elements of human dwellings. These could be made of skins and cloth, reeds or wood. In sedentary communities, where permanent lodgings are the rule, such transient fences are substituted for solidly built walls, meant to last for at least a generation and more. The first solid walls mark the beginnings of architecture, which in the Ancient Near East can be traced to the 9th millennium BC (Palestine). Whether these early walls enclosed the actual living spaces as we would understand today, or whether they were primarily built to preserve and protect goods and agricultural produce, is not certain. The advantages of a permanent shelter must have been obvious, as the steady technological development of building walls over the ensuing millennia clearly shows. Furthermore, the whole settlement could be more effectively protected against the elements (floods, sand-storms, wind); wild animals or hostile human beings, by a strong wall.
Such free-standing perimeter walls had only a few openings which had to be made secure for structural as well as defensive reasons. Sheer vertical walls are not very stable on their own, and various different solutions were found to overcome this statical problem. The most common was the use of battered walls with a triangular section. In Egypt, wavy and undulating brick walls of great thickness surrounded sanctuaries. Buttresses also improve stability. The ultimate development of the original fence around a camp is the huge fortified enclosure wall of the Iron Age, complete with bastions, towers and broad battlements (eg BABYLON, KHORSABAD, BOGHAZKÖY).
Load-bearing walls which supported the flat or vaulted roofs were almost always vertical, though additional strengthening by buttresses or pillars occurred, particularly in monumental structures. Openings were kept to a minimum, with few doorways and small windows.
The choice of material for the building of walls depended on tradition as well as local availability. The brick wall is the typical type of wall in the Ancient Near East, even in areas where stone was readily available, such as Anatolia and Egypt. Brick walls need protection from rain and erosion by the application of plaster on the outside, and some insulation is needed against rising moisture from the ground (sand, layers of reed, a few courses of stone). Massive brick walls have ventilation holes or intermittent layers of reed mats (Egypt, Mesopotamia). Various ways of bonding ensured the internal cohesion of the brickwork. In Anatolia and North Syria, the areas most affected by earthquakes, timber beams were imbedded in the brick walls, either in horizontal layers or in a frame-system, which made the whole structure more elastic (eg Alalakh (TELL ATCHANA), CARCHEMISH, Boghazköy).
Stone walls could be built in different techniques. The simplest and most