A new war now broke out in the East. Antigonus had become the most powerful of Alexander's successors. He had conquered Eumenes, who had long defied his arms, and he now began to dispose of the provinces as he thought fit. His increasing power and ambitious projects led to a general coalition against him, consisting of Ptolemy, Seleucus, Cassander, and Lysimachus, the governor of Thrace. The war began in the year 315, and was carried on with great vehemence and alternate success in Syria, Phoenicia, Asia Minor, and Greece. After four years all parties became exhausted with the struggle, and peace was accordingly concluded in 311, on condition that the Greek cities should be free, that Cassander should retain his authority in Europe till Alexander came of age, that Ptolemy and Lysimachus should keep possession of Egypt and Thrace respectively, and that Antigonus should have the government of all Asia. This hollow peace, which had been merely patched up for the convenience of the parties concerned, was not of long duration. It seems to have been the immediate cause of another of those crimes which disgrace the history of Alexander's successors. His son, Alexander, who had now attained the age of sixteen, was still shut up with his mother Roxana in Amphipolis; and his partisans, with injudicious zeal, loudly expressed their wish that he should be released and placed upon the throne. In order to avert this event Cassander contrived the secret murder both of the mother and the son.