of cohesion; but they had learnt the lesson imperfectly and reluctantly. From this time onward we have two forces at work side by side in conflict with each other, and combining to wear out the vitality of the individual States. One of these is the desire of leading States to organise confederacies under pretext of successive dangers from Persia, or from some Greek city which had grown too powerful; the other is the reluctance of the πόλεις to coalesce into such unions. These two forces act and react on each other throughout the whole of this period.
The familiar story need not be here repeated how Athens and Sparta gradually fell apart after Salamis, and how Athens formed a great naval league for the defence of the Ægean, Sparta retaining her old leadership of the Peloponnesian States and a few others. Thus Greece came to be split into two great alliances; the one an old and well-tried institution under the foremost military and aristocratic State, representing the conditions of Hellenic development before the Persian wars; the other an entirely new organisation under the newly risen naval leader, representing that spirit of popular intelligence and political progress which we have seen ripening into the democracy of Pericles. Neither of these alliances, however, was a real federal, union; neither had a common central government sufficiently strong to constitute a State power in itself apart from the governments of its component units. The keen edge of true city life was not at first seriously blunted either by the confederacy of Delos or by the Peloponnesian League. It might
