“Walk about Zion … number her towers, consider well her ramparts, go through her citadels … ” (Psalms 48:12–13)
What distinguished an ancient village or town from a city? One thing, perhaps the most important, was fortifications. Fortifying a settlement reflected the importance attributed to it; fortifications meant that a settlement was worth defending. During the Persian and later periods (from the sixth century B.C. onward), not all cities were fortified. But before that time, in the Bronze and Iron Ages, fortification of cities was almost universal and constituted one of the chief differences between cities and villages or towns.
A settlement was fortified by surrounding it with structures that would keep an enemy out. These structures took different shapes and forms in different periods. They were invented to withstand certain weapons, and when these weapons were improved or new weapons appeared, the fortifications had to be modified to answer the problems created by the new military machinery.