These diminutive polities once formed, many causes concurred to preserve their integrity, of which the most obvious and powerful was the pride of race, and, next to this, certain religious feelings and peculiarities, which stationed gods along the frontier line of states, and rendered it impious for the worshippers of other divinities to invade or dispossess them of their lands. Communities having at first been thus isolated, numerous circumstances arose to make eternal the separation. The ready invention of the people gave to each state its heroes and heroic traditions, based, perhaps, on the exploits of border warfare, in which the ancestors of one community had suffered or inflicted injuries on the ancestors of another. Poets sprang up who celebrated these deeds in song, and every assembly, every festival, every merry-making resounded with the commemoration of deeds as galling to one people as they were glorious to the other. These prejudices, this cantonal patriotism, this tribual vanity, if I may coin a new word to express a new idea, constituted a far more impassable barrier between the diminutive states of Greece, than either mountains or rivers; though, in process of time, some few cases occurred in which very small communities were immersed and lost in greater ones. The heroism, however, with which the smallest commonwealth struggled to preserve its separate existence, the watchful jealousy, the undying solicitude, the fierce and sanguinary valour by which it hedged round its independence, the indescribable agonies of political extinction, may be seen in the examples of Ægina, Megara, Platæa, and Messenia.