Full Idea
The community, coming from several villages, when it is complete, is the city, once it has already reached (one might almost say) the limit of total self-sufficiency.
Gist of Idea
The community (of villages) becomes a city when it is totally self-sufficient
Source
Aristotle (Politics [c.332 BCE], 1252b27)
Book Reference
Aristotle: 'Politics', ed/tr. Reeve,C.D.C. [Hackett 2017], p.3
A Reaction
I suppose a group of villages might be self-sufficient, provided water supply and defences were secure. In a city it is all within easy reach. Each village can't have a full set of specialists.