Passage: After these expeditions returned home, Brennus urged and persuaded them to mount a third united expedition against central Greece, led by himself and Acichorius. The reported strength of the army of 152,000 infantry and 24,400 cavalry is impossibly large. The actual number of horsemen has to be intended half as big: Pausanias describes how they used a tactic called trimarcisia, where each cavalryman was supported by two mounted servants, who could supply him with a spare horse should he have to be dismounted, or take his place in the battle, should he be killed or wounded.

Question: Who joined Acichorius on the third expedition?
Brennus