There has been tension between Ptolemaic Egypt and the Seleucid Empire over the status of southern Syria since the battle of Ipsus (301 BCE).

In the treaty (303 BCE) that had created the victorious coalition that won at Ipsus, Ptolemy I had been promised all of Syria, but he had not sent troops to Ipsus, and in the distribution of land after the battle, Syria had been allocated to Seleucus.Ptolemy had reacted in 301 by occupying most of Syria south of Damascus, as well as much of Phoenicia.

The Ptolemies later claim Syria as far as Damascus.

This traditional Egyptian policy is aimed at providing security for the Egyptian heartland.

At the same time the Seleucids claim all of southern Syria, for similar reasons – the heartland of their empire is based around northern Syria and eastern Asia Minor.Ptolemy I and Seleucus I had avoided war between their empires, but in 283 Ptolemy had died of natural causes (the only one of the successors of Alexander the Great to do so), and in 280 Seleucus is murdered.

The first fighting between the two empires appears to have followed almost immediately in the Damascene War of 280-279 BCE, probably fought in Ionia, around the city of Miletus.Seleucus’s heir Antiochus I is faced with several enemies during this period.

He had been at war with Antigonus, is facing a rebellion in the Seleucis, his family’s homeland, and in 279 BCE the Gauls invade Macedonia, before moving on to Greece and then later into Asia Minor, which they reach by 277.

In face of the Gallic threat Antiochus and Antigonus make peace (probably 279 BCE), and agreed spheres of influence – Antigonus is to have Macedonia and Greece, Antiochus Thrace and all areas east.This alliance poses a threat to Ptolemaic Egypt, and her ambitions.

Ptolemy II possesses the powerful Egyptian fleet, and ambitions to create a maritime empire in the Aegean Sea, where he already has allies at Miletus.