|Battle of Indoplon|
|Part of The Macedonian War (Athenian Legacy)|
|Athens||Kingdom of Macedon|
|Commanders and leaders|
|Unknown: Between 16,000-21,000||Unknown: Between 17,000-22,000|
|Casualties and losses|
|Unknown: All most all||Unknown: Light|
Following the failed Athenian offensive on the western coast, Helmetrus called upon a second flow of troops to be drawn into Macedonia. The call for reinforcements gave King Amyntas a great morale boost, one he used to initiate a counter offensive. Along with the arrival of the Macedonian Regular Army, composed of some of the greatest hoplite phalanx's in the world, Amyntas quickly shifted the balance in his favor. But before Amyntas could launch a response, Helmetrus stole the momentum with his reinforcements, divided his armies, and launched a second offensive. The second offensive cornered the Macedonian army into the North-Western section of the peninsula, limiting the Macedonian trade routes to a single system. Despite the beneficial movements to the Athenians, the division of the armies gave Amyntas a excellent opportunity to strike. The Macedonian army moved in the dead of night, leaving half of its mercenary force behind as merely a token army. Avoiding the open, but constrained shore pass, the Macedonians moved over the mountains, eventually making camp on Mount Indopolon. As a result, the Athenian armies pursued Amyntas, intent on total victory.
The Athenian army arrived a mile away from Mount Indopolon a few hours after dawn, allowing the Macedonian time to prepare. They were fed breakfast and drink as the enemy army drew nearer, taking up positions that had been planned for weeks. The Athenian Army approached in standard formation, though tired and shaken after endless hours of marching. Amyntas organized his most elite troops on the wings, mostly Hypaspists and veteran Hoplites, protected by a combination of light and heavy cavalry. As the Athenian Hoplites advanced up the steep mountain, they were harassed by Peltasts and a group of Cretan archers, which nearly decimated three individual Athenian phalanx's. The Athenian army spread their lines, countering Amyntas's initial strategy of outflanking. Instead, the Athenians attacked first themselves, outflanking the Macedonian army. The southern Greeks were spread to thin though, and soon, following a series of cavalry charges and defeats on the flanks, a massive rout ensued. Despite hard fighting in the center, the Macedonians eventual terrain advantage forced the rest of the Athenian army to retreat. Most historians contribute the defeat to the lack of rest and nutrition in the Athenian army, but nonetheless, it is universally agreed that Amyntas's strategy won out the day.
The defeat of the second army was total, and forced a disbandment of the entire force. Nearly half were killed in the pursuit of the routers, while the rest dispersed amongst the country-side.
The victory at Indopolon singled out Helmetrus's army, and gave a uniting war rally to the Macedonian people.