Macedonia is an ancient Greek Kingdom, it is not a geographical term. Ancient Greece had a number of city/region-states, countries and kingdoms (and empires later on) like Athens, Sparta, Macedon, Epirus, Pontus, Ptolemy, Seleucid and many more. Ancient Greek states had alliances with each other and had infighting for power and politics. However Greeks unite when an external enemy closing by and repel them, then usually going back to internal affairs. Until then, Alexander the Great had to prove his leadership to the rest of the Greeks that he can lead, and he did. He been inspired from Aristotle and the Spartan battles. He created then the first united Greek Empire and order the Athenian ships to find a path from red sea in Egypt (Ptolemy to become) to the Indies.

❝ Macedonia is an ancient Greek Kingdom and a region of Modern Greece. ❞
— Quote said by Charalampos of Thessaloniki