2 – Battle of Orchomenus (85 BC)
If Sulla thought his crushing victory at Chaeronea was decisive, he was sorely mistaken. Archelaus received 80,000 reinforcements under the command of Dorylaus, and his new army consisted of around 90,000 men; once again outnumbering the Romans. A new Roman army under the leadership of Flaccus arrived in Greece, and while it was officially attacking the Pontic forces, its real goal was to oppose Sulla as his enemies now held power in Rome. He wasn’t aware that Flaccus was an enemy and marched to Thessaly to meet the consul.
En route to this rendezvous, he heard reports that Dorylaus landed at Chalcis with a new army in support of Archelaus. Dorylaus encountered Sulla’s forces and after a brief skirmish decided that a gradual war of attrition (the same strategy favored by Archelaus the previous year) was the best course of action. However, Archelaus clearly changed his mind over his wearing down plan. Instead, he proposed another open battle because the flat terrain around his camp at Orchomenus favored his strong cavalry force.
The Pontic commander made the mistake of allowing his men to relax once they took their positions. They outnumbered the enemy by at least 5:1 according to sources but their confidence was misplaced. Sulla proceeded to eliminate the cavalry advantage by digging trenches and ditches in the hope of forcing the enemy to fight on a boggy surface. He also asked his men to dig a ten-foot trench on each end of the battlefield to avoid being outflanked. The Pontic commander recognized the tactic and launched attacks on the Legionnaires digging the trenches.
The cavalry attack on the left flank was almost successful, but Sulla rallied his men and reinforced the flank with two additional cohorts from the other side. They regained their position and repelled a second Pontic attack. Archelaus launched a disastrous assault on the Roman center with chariots; they plunged right into the spikes planted by Sulla’s men. The Roman cavalry countered and caused panic amongst the enemy chariot horses; they bolted towards their own lines and disrupted the Pontic phalanx. Archelaus lost up to 15,000 men on day one of the battle and retreated.
Sulla attacked on the second day with more trenches, and soon, the fight turned into a complete rout. The Pontic commander had to hide in the swamp for two days to escape, but his army was destroyed. When Mithridates heard about the disaster, he ordered Archelaus to negotiate peace terms. Initially, the King of Pontus rejected the offer but after losing at the Battle of Tenedos in 85 BC, he had no choice but to agree to the original terms. Sulla quickly wrapped up his affairs in Asia Minor and Greece and returned to Rome to reclaim his standing in the city.