Wars of the Diadochi > Battle of the Hellespont
Battle of the Hellespont

Background
The Battle of the Hellespont was a major war during the Wars of the Diadochi in 321 BCE that saw the armies of Craterus and Neoptolemus face off against Eumenes. Eumenes and Neoptolemus were originally representing Perdiccas who was in control over Macedon.
Craterus began marching on Perdiccas and Macedon so the two generals rode out to meet him and stop his advance at the Hellespont River. However, Neoptolemus was jealous of Eumenes and deserted with a few hundred horses and some men to join the invading army of Craterus.
Each side was evenly matched with around 20,000 infantry but the phalanx of Craterus had many more veterans from the previous Macedonian campaigns and was thus much more experienced. Both armies approached each other with the infantry in the center and the cavalry on the wings and met each other on the European side of the river.
The Battle
Craterus led his army from the right wing and charged at Eumenes beginning the fight. The phalanx infantry engaged in a brutal standoff and Craterus was killed during this portion of the fight. Following the death of their leader the cavalry was routed and began fleeing in every direction. Leading his cavalry from the left wing Neuptolemus charged at Eumenes and engaged him in one on one combat.
In the ensuing battle Eumenes killed the traitor and surrounded the remaining infantry of Craterus. The Macedonians surrendered to their countryman and were invited to join the army of Eumenes. Many agreed to save their own lives but quickly ran away in the night to join the army of Antipater.
Impact
This battle saw the deaths of two major players in the Wars of the Diadochi but overall this was just the beginning of a brutal series of conflicts to span 40 years. The Wars of the Diadochi would ultimately weaken the various independent Hellenistic kingdoms that were born out of the conquest of Alexander and lead them to be conquered by the Roman Empire and the Parthian Empire in the coming centuries.
The Battle of the Hellespont is known as the first battle in the Wars of the Diadochi and would set the stage for the interactions between the remaining contenders for many years to come. The following complete list of Diadochi battles can be found below.