Even then actual invasion did not succeed in combining the Greeks even temporarily. That was due to the inherent difficulty in interesting Thessalians or Boeotians in the quarrels of Ionians.[47] In spite of them, the danger was at that time averted, but it did not therefore become less real. The consciousness of this ever-present danger and the bitter experiences of subjection created groups that coalesced more solidly than ever before about certain leaders, Athenians or Spartans. In the fifth and fourth centuries, the concept of a Greek race received a real outline, and the feeling of a common race pride became highly developed. This race pride showed itself principally in an over-weening confidence in the superiority of Greek arms. It is a false notion that represents the Greek as careless or contemptuously indifferent of the races about him. Never were men more eager for curious tales of out-of-the-way peoples. Their earliest historians won their chief success in this way. But Greeks had beaten back the conquerors of the world, and had maintained themselves aggressively as well. It was very natural that something of this attitude was apparent in dealing with barbarians even on terms of comity. The Greeks had at least colorable ground for believing that in military matters they were masters wherever they chose. One phrase of which some Greek writers were fond need not be taken too seriously. Barbarians, we are told, are by nature slaves.[48] It would be an error to attach much importance to the statement. Greeks did not really believe that Darius or Datames or Hamilcar was servile in character or in disposition. The expression was merely the facile chauvinism that military prestige readily stirs up in any nation. So at certain times some Englishmen were ready to call the French cowards, or Frenchmen to call Prussians so. Among the Greeks the principal basis for the statement was the fact that the activity of Greek merchants and pirates filled every city with slaves of all foreign nations. Indeed the phrase is no more than a generalized assertion of that state of things. We shall have to qualify similarly the statement now and then encountered of a natural and permanent hostility between Greeks and barbarians. It is a commonplace of Athenian orators, but it practically always concerns the real hereditary enemy of Greeks, and particularly of Athens—the Persians. It is in calling the Greeks against their ancient foe that Isocrates uses the phrase,[49] and in Demosthenes[50] it is especially based upon the hostilities so long maintained between Athens and Persia and the ancient grudge Athenians bore for the sack of their city in 480 B.C.E. The first achievement of united Hellas was the invasion of Persia, although it was under Macedonian leadership that this was done, but soldiers of Alexander appeared as Greeks to the East, and Alexander is מלך יון, _melek Yavan_, “king of Greece,” in the Book of Daniel.[51]