I know!!! wait how does this even work?

Demosthenes.

He gauged Philip's ambition to control Greece.

Demosthenes was the famous Athenian orator and statesman who tried to warn Athenians of the threat that Philip II of Macedon posed to Athenian independence and Athenian dominance over the rest of Greece. Living from 384-322 BC (or, BCE), he later participated as a leader in the Athenian revolt against Philip's son, Alexander the Great in order to reclaim leadership of the Greek states.

He belived that Philip 2 was a threat to Greek Independence.