Alexander the Great traveled the plains of Asia in the fourth century BC, determined to build a series of grand, new cities. As sites were selected, a generic plan was adapted to the particular features -- the hills, rivers, waterfronts -- of each site. Two monumental streets, the Cardo and the Decumanus, were laid out to cross each town east-west and north-south, from gate to gate. Major public buildings, theaters, palaces, gymnasia, markets, and temples were strategically placed along these principal routes. The royal administration saw to it that the main streets and public buildings along them were designed with enough formality and cohesion that altogether they formed a harmonious assemblage befitting a royal city. Individuals, on the other hand, were responsible for building the smaller-scale residential fabric of houses and workshops, extending out to the city walls.
Through all Greek and Roman cities, this idea of a monumental spine forming the central lifeline of a city persisted. Byzantine Jerusalem, as described in the Madaba mosaic plan, is a vivid illustration of the principle. The walled city is punctuated by the city gates, which are the points of principal entry, and the Cardo Maximus, a sixty-five-foot-wide colonnaded street, stretches north-south, between two main gates. The