The Greeks never thought to unite all Greek speakers in one political union. Because each Greek gloried in his singular excellence—and each Greek clan gloried similarly—it was hard enough to unite a city. Each city or polis—from which come our words politics, politician, metropolis—thought itself unrivaled in some essential quality and reveled in its reputation.
Ch.IV The Politician and the Playwright: How to Rule - Sailing the Wine-Dark Sea: Why the Greeks Matter (2003)