Alexander, who is initially disgusted with his brother's inferior intellect, learns to love him before he sets out to conquer the world.
In the Japanese fiction manga Historie, he was shown as an intellectually disabled young child that became happy when Eumenes made him a toy chariot and became sad when Alexander the Great destroyed his toy.
Arrhidaeus' whereabouts during the reign of his brother Alexander are unclear from the extant sources; what is certain is that no civil or military command was given to him in those thirteen years (336–323 BC).
It was immediately decided that Philip Arrhidaeus would reign, but not rule: this was to be the prerogative of the new regent, Perdiccas. Head of Herakles right, wearing lion skin headdress / [BASILEWS FILIPPOU], Zeus Aëtophoros seated left; wheel and monogram in left field, monogram below throne.
When news arrived in Macedonia that Arrhidaeus had been chosen as king, Cynane, a daughter of Philip II, developed a plan to travel to Asia and offer the new king her daughter Eurydice for wife. Eurydice's chance to increase her husband's power came when the first war of the Diadochi sealed the fate of Perdiccas, making a new settlement necessary.
359 BC – 25 December, 317 BC) reigned as king of Macedonia from after 11 June 323 BC until his death.
He was a son of King Philip II of Macedon by Philinna of Larissa, and thus an elder half-brother of Alexander the Great.