The world-politics of this period are almost as confused as the relationships which were the outcome of the matrimonial alliances contracted by the principal actors on the world's stage. How bewildering these alliances were may be judged from what Mr. Tarn says of Stratonice, the daughter of Antiochus I., who married Demetrius, the son of Antigonus: "Stratonice was her husband's first cousin and also his aunt, her mother-in-law's half-sister and also her niece, her father-in-law's niece, her own mother's granddaughter-in-law, and perhaps other things which the curious may work out." Mr. Tarn has unravelled the tangled political web with singular lucidity. Here it must be sufficient to say that, after the death of Pyrrhus, a conflict between Macedonia and Egypt, which stood at the head of an anti-Macedonian coalition of which Athens, Epirus, and Sparta were the principal members, became inevitable. The rivalry between the two States led to the Chremonidean war--so called because in 266 the Athenian Chremonides moved the declaration of war against Antigonus. The result of the war was that on land Antigonus remained the complete master of the situation. With true political instinct, however, he recognised the truth of that maxim which history teaches from the days of Aegospotami to those of Trafalgar, viz. that the execution of an imperial policy is impossible without the command of the sea. This command had been secured by his predecessors, but had fallen to Egypt after the fine fleet created by Demetrius the Besieger had been shattered in 280 by Ptolemy Keraunos with the help of the navy which had been created by Lysimachus. Antigonus decided to regain the power which had been lost. His efforts were at first frustrated by the wily and wealthy Egyptian monarch, who knew the power of gold. "Egypt neither moved a man nor launched a ship, but Antigonus found himself brought up short, his friends gone, his fleet paralysed." Then death came unexpectedly to his aid and removed his principal enemies. His great opponent, the masterful Arsinoë, who had engineered the Chremonidean war, was already dead, and, in Mr. Tarn's words, "comfortably deified." Other important deaths now followed in rapid succession. Alexander of Corinth, Antiochus, and Ptolemy all passed away. "The imposing edifice reared by Ptolemy's diplomacy suddenly collapsed like the card-house of a little child." Antigonus was not the man to neglect the opportunity thus afforded to him. Though now advanced in years, he reorganised his navy and made an alliance with Rhodes, with the result that "the sea power of Egypt went down, never to rise again." Then he triumphantly dedicated his flagship to the Delian Apollo. The possession of Delos had always been one of the main objects of his ambition. It did more than symbolise the rule of the seas. It definitely brought within the sphere of Macedonian influence one of the greatest centres of Greek religious thought.