He fled to King Lysimachus of Thrace and Macedon where he was involved in court intrigue that led to the fall of that kingdom in 281 BC to Seleucus I, whom he then assassinated.

He then seized the throne of Macedon, which he ruled for seventeen months before his death in battle against the Gauls in early 279 BC.

[6][7] Following his departure from Egypt, Ptolemy Ceraunus went to the court of Lysimachus, who ruled Macedon, Thrace and western Asia Minor and who may have been his father-in-law.

But as Seleucus was sacrificing at a place called Argos, Ptolemy Ceraunus murdered him, intending to seize control of the territories of his former protector.

They have the same design as earlier coinage of Lysimachus: the head of Alexander the Great with the horn of Ammon on the obverse and a depiction of Athena seated, holding up a Nike on the reverse.

However, Hollstein has argued that these were coins of Ptolemy Ceraunus, intended to present him as the legitimate heir of Lysimachus and in possession of a formidable force of elephants.

[18] Ptolemy Ceraunus also made an alliance with Pyrrhus of Epirus, who had controlled the western portion of Macedon from 288-284 BC, ending the threat of attack from him.

The alliance freed Pyrrhus to invade Italy to fight against the Roman Republic in the Pyrrhic War.

[26] When the forces joined battle, Ceraunus was wounded and captured by the Gauls, who killed him, mounted his head on a spear and carried it around the battlefield.

[27][15][28] Ptolemy Ceraunus' death brought anarchy, as the Gauls streamed through the rest of Greece and into Asia Minor.

Immediately after Ceraunus' death the throne of Macedon was taken by his younger brother Meleager, but he was deposed by his troops within months.

This situation lasted about two years, until Antigonos Gonatas defeated the Gauls in a battle near Lysimachia, Thrace, in 277 BC.

Christopher Bennett proposes that she may have been a daughter of Lysimachus, with whom Ptolemy I contracted a number of marriage alliances in those years.

[2] Ptolemy agreed to marry Lysimachus' widow Arsinoe II, his own half-sister, in late 281 or early 280 BC, as part of a plot to seize the city of Cassandreia and murder her children.