Must've been a pretty big wall /sarcasm.
so there was not the great division between urban and rural which resulted from the cities' growth.
Actually, the first cities emerged as a place of market for nearby farmers to sell and trade their goods. They were dependent upon the agriculture, not the other way around.
Barring times of famine providing a society with food is not the greatest problem it faces.
Famines were commonplace in cities until the early 18th century and happened with far greater frequency than major wars, of which you'd get 2 or maybe 3 a century as opposed to a dozen or more famines.
The first cities had the market, the citadel and the temple. Babylon had huge walls miles in circumference. Farming never could get far without the protection of the armies which cities generated. Raiders would just come and take everything without impunity until the cities developed.
Famines which produced widescale death were not common in Europe. Nor were they more common than war.