This likely would have led to war, but it was Seleukos IV's turn to perish at the hands of a conspiracy, murdered by his chief minister, one Heliodorus.
The proper heir to the throne was Demetrios, eldest son of Seleukos IV, who was a hostage in Rome.
There remained only family matters standing in the way of Antiochus IV, in the form of his sister, the widowed queen of Seleukos IV, and her four- or five-year-old son Antiochus, who was, in the wake of his father's death, the legitimate heir.
On his way to the east, Antigonos was careful to conciliate Seleukos; on his way back westwards, he decided that Seleukos was a danger, and scared him off.
Seleukos had been only a junior general amongst Alexander's men.
Seleukos rode to Egypt with a collection of about fifty followers.
In 312 BC, after three years of war, Ptolemy and Seleukos succeeded in beating Antigonos' army in battle at Gaza in Palestine.
Seleukos, in this as in many other respects, was different.
Seleukos enticed Nikanor's army into territory which was marshy and seamed by canals, and then in a surprise attack killed several of the senior officers and drove Nikanor off.
So, within a year of setting off with a thousand men and no land, Seleukos now ruled a territory stretching from the Euphrates to eastern Iran, nearly 2,000 kilometres from east to west, and commanded an army of 25,000 soldiers.
Apart from his success as an empire builder, it is his treatment of the people he ruled which distinguishes Seleukos from all the other Macedonian conquerors and rulers.
18) Nobody will blame the excavator for not being able to give the Greek name of the city, for not having discovered any sure evidence about the exact date of its foundation (already in the time of Alexander or under Seleukos the First), nor for being unable to state whether the palace was a royal residence or only administrative quarters inhabited by a governor and his retinue.
Lyonnet from correlating the phases in Hellenistic pottery with political events, Alexander's conquest (white ceramics) and Seleukos I's reconquest (grey-black ceramics).