Following Alexander the Great’s death in 323 BC, his generals began fighting over the empire he had created. Within a decade two leading factions emerged. The first, led by the grizzled Macedonian veteran Antigonus the One-Eyed and his son Demetrius, wanted to rule over an intact empire. The opposing faction included Cassander, regent of the Macedonian homeland, and Ptolemy, satrap of Egypt. In 315 BC Antigonus quarreled with Seleucus, satrap of Babylon (in present-day Iraq), and drove him from his province. Seleucus fled to join Ptolemy in Egypt.
In late 312 BC, Demetrius’ army was in Palestine. At Seleucus’ urging, Ptolemy moved out of Egypt to confront Demetrius with 18,000 infantry and 4,000 cavalry. In response, Demetrius concentrated his forces near the city of Gaza. His friends urged him not to fight Ptolemy and Seleucus, who were veterans of Alexander’s wars and skilled generals in their own right. Demetrius, who was in his mid-20s and exercising his first command independent of his father, nevertheless arrayed his army for battle in late December.
Demetrius had roughly 13,000 infantry and 4,400 cavalry. But while his army was smaller than Ptolemy’s, Demetrius had an asset Ptolemy lacked —43 Indian war elephants. Demetrius arranged the army in the standard pattern (cavalry on the wings, infantry in the center) but with a twist: He heavily reinforced his left with almost 3,000 cavalry. In front of the cavalry he placed 30 elephants, with light infantry filling the gaps between animals.
When Ptolemy and Seleucus learned of Demetrius’ formation, they moved to counter his left, beefing up their right with 3,000 cavalry. In front of this force, they placed a nasty surprise for the elephants—a series of spiked planks linked by chains. Covering these devices were javelineers and archers, who were ordered to shoot at both the elephants and their mahouts.
The battle began with a clash between the cavalry of Demetrius’ left and Ptolemy’s right. Demetrius initially had the upper hand, but then Ptolemy and Seleucus brought in reinforcements, and the clash resumed. Both sides were armed with the xyston, a thrusting lance; when these shattered, combat continued with swords.
Then Demetrius played what he considered his trump card, calling up the elephants. But they encountered unexpected resistance. Some were injured by the spikes and, maddened by pain, threw the line into disorder. Ptolemy’s archers and javelineers also injured many elephants and picked off their drivers. Ultimately, Ptolemy’s men badly disabled the elephants and were able to capture them.
This development panicked Demetrius’ cavalrymen, who fled, ignoring their leader’s entreaties to stand firm. Then Demetrius joined the flight, bypassing Gaza, which Ptolemy captured. Some of Demetrius’ infantry also abandoned their equipment and fled, but about 8,000 of them were captured.
Demetrius also suffered more than 500 men killed, most of them cavalrymen. Demetrius’ defeat opened the road to Babylonia. Several weeks after their victory at Gaza, Seleucus asked Ptolemy for troops with which to retake his former province. Ptolemy agreed, providing 800 infantry and 200 cavalry. Seleucus headed east in early 311 BC, and with Ptolemy’s troops and recruits gathered en route, he retook Babylon.
■ Don’t put your faith in “miracle weapons.” Demetrius expected his elephants to win the battle. He was wrong.
■ Adapt or die. Ptolemy and Seleucus had seen elephants in action during Alexander’s Indian campaign and were able to devise countermeasures.
■ Inexperience kills. Antigonus the One-Eyed assigned Peithon, Alexander’s onetime bodyguard, to assist the inexperienced Demetrius. It didn’t help: Peithon wound up dead on the field.
■ Stay flexible. Ptolemy and Seleucus had planned to attack with cavalry on their left. But when they learned that Demetrius had strengthened his left, they quickly transferred men to their right.
■ Panic turns defeat into disaster. As Demetrius’ fleeing cavalry approached the walls of Gaza, some men rushed the gates to retrieve baggage. The resulting chaos prevented guards from closing the gates, and Ptolemy captured Gaza.
■ Open a new front. By re-establishing himself in Babylon, Seleucus forced Antigonus to split his resources between two fronts. In the end, Seleucus was instrumental in engineering Antigonus’ final defeat in 301 BC.
Originally published in the May 2009 issue of Military History. To subscribe, click here.