Seleucus II Callinicus

Seleucus II Callinicus was the second son of Antiochus II and the fourth king of the Seleucid Empire.
Rise to Power.
After Antiochus II died his second wife Berenice declared her son Antiochus king at Antioch while his first wife Laodice declared her son Seleucus king in Ephesus. Since Antiochus was too young to be able to rule, Seleucus and Laodice had Berenice killed so that Seleucus no longer had any challenger for his throne. Ptolemy III Euergetes was angry about this so he invaded Syria and started a war.
Third Syrian War.
Seleucus appointed his brother Antiochus Hierax as viceroy of the Seleucid Empire so that he could have Antiochus Hierax rule Syria for him while he left to fight Ptolemy. Ptolemy won most of the battles but Seleucus won enough of them that in 241 B.C.E. they agreed to a treaty which said that Ptolemy ruled all the lands he conquered but that Seleucus would stay ruler of the Seleucid Empire. 
Antiochus Hierax.
While Seleucus was off fighting the war, his brother Antiochus Hierax tried to become the new king in Asia Minor. So Seleucus started a war with Hierax to take it back. The war went on for two years and ended in a stalemate. 
Parthia.
After this, Parthia left the Seleucid Empire and Seleucus went to war to get it back but lost. 
Rebellion of Stratonice.
After Hierax died, Seleucus’s aunt Stratonice asked him to marry her. He said no so she led a rebellion against him. Seleucus crushed the revolt and had her executed. 
Death.
In 225 B.C.E, Seleucus fell off his horse and died. His son Alexander became king and changed his name to Seleucus III Ceraunus.