and Rome alone saved the dynasty from complete destruction. * * * * * A variety of motives actuated the early Ptolemies in their struggle for foreign dominions. Pride of possession was among them, of course. The court poet Callimachus[86] struck a responsive chord when, in his poem on the death of Arsinoë, the sister-wife of Philadelphus, he has the sad news flashed from beacon point to beacon point till it reaches Lemnos at the outer edge of the empire. National honor is a strong motive for action, but it is commonly stirred by the fear of losing something possessed rather than by the hope of acquiring something new. Hence we must look deeper for the reasons which led cautious statesmen like the first two Ptolemies to place round Egypt its girdle of power. The motive suggested by Polybius[87] is quite different. It was with regard to possible movements on the part of the monarchs of Syria, Asia Minor, Thrace, and Macedon that the Ptolemies held, as he says, "the most important towns, places, and harbors along the whole coast" of the eastern Mediterranean. And there can be no doubt that he is right in attributing this rather malicious aim to them. They were, doubtless, great intriguers. But to Polybius, looking on from without, from one of the districts which had been affected by the close proximity of Egyptian garrisons and naval stations, the connection of these posts with the foreign policy of the Ptolemies was apt to obtrude itself to the exclusion of everything else. Nowadays historians are prone to a similar onesidedness because of the close attention they give to economic factors. They are quite right when they stress the importance of Ptolemaic naval power and of the vantage-points held in Europe and Asia for the development of Alexandrian commerce. The lighthouse which Ptolemy erected at the mouth of the Nile at a cost of a million dollars (eight hundred talents) was not only one of the seven wonders of the world: it was a messenger of good will to the trading vessels which came from all the dependencies with or without cargoes, to get for Greek consumption the varied products of the Alexandrian factories, the Egyptian grain-fields, and the Nile-borne traffic of Arabia, India, Somaliland, and Ethiopia. What the lighthouse symbolizes, the growth of Alexandria to half a million in a hundred years proves: the magnitude of the commerce which the transmarine possessions of Egypt stimulated, when they did not originate it. Where the economic historians are wrong, however, is in doing what Polybius did. _He_ made the imperial policy of the early Ptolemies primarily foreign; _they_ make it primarily commercial. The truth is that it was dictated also by the plain necessities of the domestic situation. Let us see what that was. * * * * *