Philip III of Macedon

Born Arrhidaeus around 357 BC, he was Philip II's son by a Thessalian woman named Philinna — which made him Alexander the Great's elder half-brother. As he grew it became clear he had learning difficulties; ancient gossip blamed Olympias and poison, though that's likely fiction. Alexander kept him close on campaign, both out of affection and to keep him from becoming a tool for rivals. When Alexander died in Babylon in 323 BC, the army proclaimed Arrhidaeus king and gave him his father's name. He ruled nothing. For six years he was shuttled between generals who used his royal blood as a licens…