When Perdiccas died, Antigonus was named his successor, and became governor of all the Eastern province. He no sooner heard that Cassander had murdered Alexander’s family, than he marched westward, intending to avenge the crime.
On his way, Antigonus passed through Syria, the land governed by Seleucus, and asked that ruler how he had spent the money of the kingdom. Seleucus, who had a bad conscience, instead of answering, ran away to Egypt, where he became a friend of Ptolemy.
Then, fearing that they would not be able to fight against Antigonus successfully, these two generals persuaded Cassander, ruler of Macedon, and Lysimachus, ruler of Thrace, to join them.
For several years the war was kept up between the four allies on one side, and Antigonus and his son Demetrius on the other. The field of battle was principally in Asia Minor. The fighting continued until the generals became weary of warfare, and concluded to make peace.
A treaty was then signed, settling the claims of all parties, and providing that all the Greek cities should have their freedom. This done, each went back to his own province; but it soon became evident that the peace would not last, for Cassander did not keep his promise to make the Greek states free.
When Cassander’s wrongdoing became known, the generals called upon Demetrius to bring him to terms. The Athenians were so pleased when they heard of this, that they received Demetrius with great joy.
Demetrius was such a good general that he soon managed to defeat Cassander at Thermopylae; and when he came back to Athens in triumph, the happy people gave him the title of “The Preserver,” called a month by his name, lodged him in the Parthenon, and worshiped him as a god. Some time after this, Demetrius conquered Ptolemy, who had shown that he would not abide by the treaty either. This victory was so great, that Demetrius’ soldiers said he deserved a reward, and named him King of Syria.