Soon after Seleucus' return, the supporters of Antigonus tried to get Babylon back.
Nicanor was the new satrap of Media and the strategos of the eastern provinces.
His army had about 17,000 soldiers.
Evagoras, the satrap of Aria, was allied with him.
It was obvious that Seleucus' small force could not defeat the two in battle.
Seleucus hid his armies in the marshes that surrounded the area where Nicanor was planning to cross the Tigris and made a surprise attack during the night.
Evagoras fell in the beginning of the battle and Nicanor was cut off from his forces.
The news about the death of Evagoras spread among the soldiers, who started to surrender en masse.
Almost all of them agreed to fight under Seleucus.
Nicanor escaped with only a few men.

Even though Seleucus now had about 20,000 soldiers, they were not enough to withstand the forces of Antigonus.
He also did not know when Antigonus would begin his counterattack.
On the other hand, he knew that at least two eastern provinces did not have a satrap.
A great majority of his own troops were from these provinces.
Some of Evagoras' troops were Persian.
Perhaps a portion of the troops were Eumenes' soldiers, who had a reason to hate Antigonus.
Seleucus decided to take advantage of this situation.

Seleucus spread different stories among the provinces and the soldiers.
According to one of them, he had in a dream seen Alexander standing beside him.
Eumenes had tried to use a similar propaganda trick.
Antigonus, who had been in Asia Minor while Seleucus had been in the east with Alexander, could not use Alexander in his own propaganda.
Seleucus, being Macedonian, had the ability to gain the trust of the Macedonians among his troops, which was not the case with Eumenes.

After becoming once again satrap of Babylon, Seleucus became much more aggressive in his politics.
In a short time he conquered Media and Susiana.
Diodorus Siculus reports that Seleucus also conquered other nearby areas, which might refer to Persis, Aria or Parthia.
Seleucus did not reach Bactria and Sogdiana.
The satrap of the former was Stasanor, who had remained neutral during the conflicts.
After the defeat of Nikanor's army, there was no force in the east that could have opposed Seleucus.
It is uncertain how Seleucus arranged the administration of the provinces he had conquered.
Most satraps had died.
In theory, Polyperchon was still the lawful successor of Antipater and the official regent of the Macedonian kingdom.
It was his duty to select the satraps.
However, Polyperchon was still allied with Antigonus and thus an enemy of Seleucus.
Soon after Seleucus' return, the supporters of Antigonus tried to get Babylon back. Nicanor was the new satrap of Media and the strategos of the eastern provinces. His army had about 17,000 soldiers. Evagoras, the satrap of Aria, was allied with him. It was obvious that Seleucus' small force could not defeat the two in battle. Seleucus hid his armies in the marshes that surrounded the area where Nicanor was planning to cross the Tigris and made a surprise attack during the night. Evagoras fell in the beginning of the battle and Nicanor was cut off from his forces. The news about the death of Evagoras spread among the soldiers, who started to surrender en masse. Almost all of them agreed to fight under Seleucus. Nicanor escaped with only a few men.
Even though Seleucus now had about 20,000 soldiers, they were not enough to withstand the forces of Antigonus. He also did not know when Antigonus would begin his counterattack. On the other hand, he knew that at least two eastern provinces did not have a satrap. A great majority of his own troops were from these provinces. Some of Evagoras' troops were Persian. Perhaps a portion of the troops were Eumenes' soldiers, who had a reason to hate Antigonus. Seleucus decided to take advantage of this situation.
Seleucus spread different stories among the provinces and the soldiers. According to one of them, he had in a dream seen Alexander standing beside him. Eumenes had tried to use a similar propaganda trick. Antigonus, who had been in Asia Minor while Seleucus had been in the east with Alexander, could not use Alexander in his own propaganda. Seleucus, being Macedonian, had the ability to gain the trust of the Macedonians among his troops, which was not the case with Eumenes.
After becoming once again satrap of Babylon, Seleucus became much more aggressive in his politics. In a short time he conquered Media and Susiana. Diodorus Siculus reports that Seleucus also conquered other nearby areas, which might refer to Persis, Aria or Parthia. Seleucus did not reach Bactria and Sogdiana. The satrap of the former was Stasanor, who had remained neutral during the conflicts. After the defeat of Nikanor's army, there was no force in the east that could have opposed Seleucus. It is uncertain how Seleucus arranged the administration of the provinces he had conquered. Most satraps had died. In theory, Polyperchon was still the lawful successor of Antipater and the official regent of the Macedonian kingdom. It was his duty to select the satraps. However, Polyperchon was still allied with Antigonus and thus an enemy of Seleucus.
Seleucus I Nicator