Wars of the Diadochi > Babylonian War
The Babylonian War was a series of battles between 311 BCE and 309 BCE fought by Antigonus I Monophthalmus and Seleucus I Nicator over control in Mesopotamia. The final outcome saw Seleucus victorious and allowed him to establish the Seleucid Empire, also removing all possibility of the original empire of Alexander III the Great to ever be reformed for his successor. At this point in the wars Antigonus I had established his new kingdom in the territory of Syria and Anatolia along the eastern shores of the Mediterranean and was growing in power.
This caused concern for the other Diadochi such as Ptolemy I who was ruling Ptolemaic Kingdom and Cassander who was ruling over Macedon but they were defeated by the military prowess of the experienced battlefield commander. This was known as the Third War of the Diadochi and was concluded in December of 311 BCE and was called the Peace of the Dynasts. With this treaty they agreed to accept each others kingdoms and stop the fighting. However, it did not include Seleucus who was previously the satrap of Babylonia but removed from office by Antigonus in 316 BCE.
Seeking to build an empire of his own, he was given an army by Ptolemy and this kicked off the Babylonian Wars. The outcome of this was would lead directly to the Battle of Ipsus and eventually to the establishment of the Seleucid Empire. It led to a decline in power of Antigonus I and laid the foundations for the Fourth War of the Diadochi which was to become the final after almost forty years of fighting since the death of Alexander the Great. Most of the details and primary accounts of this war and its conflicts comes from the Diadochi Chronicle which were ancient clay tablets written in cuneiform.
Seleucus marched in with his army provided by Ptolemy towards Babylon and was soon joined by reinforcements from the city of Harran. He reached the city with his army in May of 311 BCE and walked right through the city, being easily recognized as the new ruler of Babylonia. However, this did not sit well with the elite and soldiers that remained loyal to Antigonus which still existed in the palace complex.
Seleucus idea was simply to wait them out and take a page out of Alexander's playbook and maybe the one from Cyrus the Great before him. He ordered his army and engineers to start by building a dam to back up the Euphrates River and form a reservoir lake. When the lake built up to considerable size after a few months he broke in the dam in August and washed away the fortress walls.
Antigonus still controlled a considerable portion of territory during this period and his satraps in Media named Nicanor and Euagoras of Aria decided to respond by raising an army of 10,000 infantry and 7,000 cavalry. They could not allow Seleucus to cut them off from the territory on the eastern Mediterranean which would make them easier to conquer so they hoped to defeat Seleucus himself.
Not so easily fooled, Seleucus had planned for this and since September of 311 BCE had positioned a light reserve force of 3,000 infantry and 400 cavalry at the Tigris River anticipating the soldiers from the east. As the invading army approached the reserve force hid in the marshes and attacked them by surprise at night, decimating the Median and Arian forces. Nicanor was killed in the battle and the forces from Media soon switched sides. Seleucus used the momentum to advance east through the Zagros Mountains and seize the capital city of Ecbatana which belonged to . He then continued into the city of Susa which left Seleucus in control of a massive amount of territory quickly.
By the time that Antigonus was signing the Peace of the Dynasts in December of 311 BCE he received word of his satraps defeat and the conquering of Babylonia, Media and Elam. Outraged he ordered his son Demetrius I Poliorcetes to take an army and reclaim the territory. By the time Demetrius reached Babylon in the spring of 310 BCE the army of Seleucus was still campaigning throughout the eastern territories so he tried to besiege the city.
Yet, the vassals that Seleucus had installed stood by his side and repelled the invading army and Demetrius was forced to retreat west back to the territory of Syria. Antigonus I himself would personally lead the next campaign to reclaim Babylon in the fall of 310 BCE and he was able to fight his way through and enter the city. However, he would eventually be repelled as well by March of 309 BCE and he was forced to retreat northwest to the territory of Assyria. Seleucus, who had heard of Antigonus marching on Babylon was able to meet the forces of Antigonus as they were retreating and ordered a surprise attack.
While the forces of Antigonus were eating breakfast the army of Seleucus overran their camp, having previously eaten in the dead of night. They won a decisive victory against Antigonus and cemented the rule of Seleucus in the region.
Following the end of the Babylonian Wars the military of Antigonus was forced to retreat and ultimately surrendered all of the eastern provinces of the empire to Seleucus. The Seleucid Empire was immediately established in the territories of Babylonia, Elam and Media. Following this event Seleucus would undertake a campaign much like Alexander before him and conquer all of the eastern satrapies before reaching the Indus River and forming a treaty with the Maurya Empire and its leader Chandragupta Maurya.
In exchange for giving him parts of the eastern Seleucid Empire such as Bactria and others the Indian emperor gave him a formidable fighting force of 500 war elephants that would allow him to easily establish military dominance in Mesopotamia and beyond. At this point in time the only people that have rivaled Seleucus for the largest empire in ancient history are Alexander the Great himself and the Achaemenid Empire before him.
Following the Babylonian War the unification of Alexander's previous empire for his heirs was impossible. The events of this war led directly to the Battle of Ipsus and the Fourth War of the Diadochi.The peace treaty of 311 did not inaugurate a true age of peace. On the contrary. Every signatory had a secret agenda and used the warless years to build new armies and prepare for war. The period of uneasy peace lasted until 307. Antigonus Monophthalmus used the truce to attack Seleucus, the satrap of Babylonia, who had not signed the treaty. Seleucus' arrival at Babylon can be dated between 13 May and 1 June 311 (text; more). Although there was some fighting in one of the citadels, Seleucus' assault on the world's largest city had been an easy success, which had been facilitated by the fact that Antigonus' satrap of Babylon, Peithon, had died a few months earlier in the battle of Gaza. From the Babylonian Diadochi Chronicle, we learn that Seleucus used a strategem involving water of the Euphrates, but the details remain unclear. Almost immediately, the satrap of Media, Antigonus' friend Nicanor, and the satrap of Aria, Euagoras, marched on Babylon, but Seleucus was waiting for them near the Tigris. When Euagoras was killed during the battle, his men went over to Seleucus, and Nicanor was forced to retreat. Seleucus immediately took Nicanor's capital Ecbatana and enlisted his soldiers in his own army. He now marched to the south, where he captured Susa and added Elam to his possessions. Soon, Media was added. In a half year's time, he had become a powerful ruler, and he accepted the title Nicator, 'victor'. He was still in Media when Demetrius arrived on the scene (early 310; text). By this time, the peace treaty had been concluded, and Antigonus could afford to send soldiers to the east. The attackers started to besiege the two citadels of Babylon. When the first one was captured and looted, the main force left the city, leaving one Archelaus as satrap to take the second citadel. Demetrius had orders to return, and Seleucus organized a guerilla war against Archelaus. In August 310, Antigonus himself arrived in Babylon (text). There were street-fights, but Antigonus was unable to capture all buildings he wanted to take, and appears to have left the city in March 309, although the struggle in the countryside lasted until after 10 April 309, New Year's day. During the summer, Antigonus conducted punitive campaigns in the neighborhood, and Seleucus continued the guerilla. The struggle must have had a devastating effect on city and countryside of Babylon. The commodity prices rose to incredible heights, as is recorded by the the author of the Babylonian Diadochi Chronicle. Finally, Seleucus and Antigonus met each other in a full-scale battle. According to the Greek author Polyaenus (text), Seleucus ordered his men to have breakfast during the night, and attacked before dawn. His enemies were hungry and unarmed, and Antigonus was forced to go back to Syria (30 or 31 August). The two parties must have concluded a peace treaty, because Seleucus proceeded to conquer the eastern satrapies, and Antigonus was active in the west. He had every reason to return. In the meantime, Ptolemy had added Cyprus to his territories, and moved to the Aegean Sea, where he gained a bridgehead on the island Cos (winter 309/308). From there, he sailed to Delos, where he reorganized the Nesiotic League (above), which would support the ruler of Egypt. Antigonus was compelled to focus on the west. Seleucus now had a free hand to go to the east. He conquered Bactria and invaded India. His victories were duly commemorated with a coin issue - although the particlar coin to the left was struck a quarter of a century after the events.
History Archive: Diadochi Chronicle