The most powerful man in the empire after the death of Perdiccas was Antipater.
Perdiccas' opponents gathered in Triparadisos, where the empire of Alexander was partitioned again (the Treaty of Triparadisus 321 BC).

At Triparadisos the soldiers had become mutinous and were planning to murder their master Antipater.
Seleucus and Antigonus, however, prevented this.
For betraying Perdiccas, Seleucus was awarded the rich province of Babylon.
This decision may have been Antigonus' idea.
Seleucus' Babylon was surrounded by Peucestas, the satrap of Persis; Antigenes, the new satrap of Susiana and Peithon of Media.
Babylon was one of the wealthiest provinces of the empire, but its military power was insignificant.
It is possible that Antipater divided the eastern provinces so that no single satrap could rise above the others in power.

After the death of Alexander, Archon of Pella was chosen satrap of Babylon.
Perdiccas, however, had plans to supersede Archon and nominate Docimus as his successor.
During his invasion of Egypt, Perdiccas sent Docimus along with his detachments to Babylon.
Archon waged war against him, but fell in battle.
Thus, Docimus was not intending to give Babylon to Seleucus without a fight.
It is not certain how Seleucus took Babylon from Docimus, but according to one Babylonian chronicle an important building was destroyed in the city during the summer or winter of 320 BC.
Other Babylonian sources state that Seleucus arrived in Babylon in October or November 320 BC.
Despite the presumed battle, Docimus was able to escape.

Meanwhile, the empire was once again in turmoil.
Peithon, the satrap of Media, assassinated Philip, the satrap of Parthia, and replaced him with his brother Eudemus as the new satrap.
In the west Antigonus and Eumenes waged war against each other.
Just like Peithon and Seleucus, Eumenes was one of the former supporters of Perdiccas.
Seleucus' biggest problem was, however, Babylon itself.
The locals had rebelled against Archon and supported Docimus.
The Babylonian priesthood had great influence over the region.
Babylon also had a sizeable population of Macedonian and Greek veterans of Alexander's army.
Seleucus won over the priests with monetary gifts and bribes.
The most powerful man in the empire after the death of Perdiccas was Antipater. Perdiccas' opponents gathered in Triparadisos, where the empire of Alexander was partitioned again (the Treaty of Triparadisus 321 BC).
At Triparadisos the soldiers had become mutinous and were planning to murder their master Antipater. Seleucus and Antigonus, however, prevented this. For betraying Perdiccas, Seleucus was awarded the rich province of Babylon. This decision may have been Antigonus' idea. Seleucus' Babylon was surrounded by Peucestas, the satrap of Persis; Antigenes, the new satrap of Susiana and Peithon of Media. Babylon was one of the wealthiest provinces of the empire, but its military power was insignificant. It is possible that Antipater divided the eastern provinces so that no single satrap could rise above the others in power.
After the death of Alexander, Archon of Pella was chosen satrap of Babylon. Perdiccas, however, had plans to supersede Archon and nominate Docimus as his successor. During his invasion of Egypt, Perdiccas sent Docimus along with his detachments to Babylon. Archon waged war against him, but fell in battle. Thus, Docimus was not intending to give Babylon to Seleucus without a fight. It is not certain how Seleucus took Babylon from Docimus, but according to one Babylonian chronicle an important building was destroyed in the city during the summer or winter of 320 BC. Other Babylonian sources state that Seleucus arrived in Babylon in October or November 320 BC. Despite the presumed battle, Docimus was able to escape.
Meanwhile, the empire was once again in turmoil. Peithon, the satrap of Media, assassinated Philip, the satrap of Parthia, and replaced him with his brother Eudemus as the new satrap. In the west Antigonus and Eumenes waged war against each other. Just like Peithon and Seleucus, Eumenes was one of the former supporters of Perdiccas. Seleucus' biggest problem was, however, Babylon itself. The locals had rebelled against Archon and supported Docimus. The Babylonian priesthood had great influence over the region. Babylon also had a sizeable population of Macedonian and Greek veterans of Alexander's army. Seleucus won over the priests with monetary gifts and bribes.
Seleucus I Nicator