Mantinea was equal to any city in Arcadia, consequently it was equal to Megalopolis, which was fifty stadia, or sixty miles and a quarter in circumference. But Mantinea had only 3000 citizens. The Greek cities, therefore, contained often fields and gardens, together with the houses, and we cannot judge of them by the extent of their walls. Athens contained no more than 10,000 houses, yet its walls, with the sea-coast, were about twenty miles in extent. Syracuse was twenty-two miles in circumference, yet was scarcely ever spoken of by the ancients as more populous than Athens. Babylon was a square of fifteen miles, or sixty miles in circuit; but it contained large cultivated fields and enclosures, as we learn from Pliny. Though Aurelian’s wall was fifty miles in circumference, the circuit of all the thirteen divisions of Rome, taken apart, according to Publius Victor, was only about forty-three miles. When an enemy invaded the country all the inhabitants retired within the walls of the ancient cities, with their cattle and furniture and instruments of husbandry, and the great height to which the walls were raised enabled a small number to defend them with facility. “Sparta,” says Xenophon,​[82] “is one of the cities of Greece that has the fewest inhabitants.” Yet Polybius says that it was forty-eight stadia in circumference, and was round. All the Ætolians able to bear arms in Antipater’s time, deducting some few garrisons, were but ten thousand men. Polybius tells us that the Achæan league might, without any inconvenience, march thirty or forty thousand men; and this account seems very probable, for that league comprehended the greatest part of Peloponnesus. Yet Pausanias, speaking of the same period, says that all the Achæans able to bear arms, even when several manumitted slaves were joined to them, did not amount to fifteen thousand. The Thessalians, till their final conquest by the Romans, were in all ages turbulent, factious, seditious, disorderly. It is not, therefore, natural to suppose that that part of Greece abounded much in people. We are told by Thucydides that the part of Peloponnesus adjoining to Pylos was desert and uncultivated. Herodotus says that Macedonia was full of lions and wild bulls, animals which can only inhabit vast unpeopled forests. These were the two extremities of Greece. All the inhabitants of Epirus, of all ages, sexes, and conditions, who were sold by Paulus Æmilius, amounted only to 150,000. Yet Epirus might be double the extent of Yorkshire.