This is a support quest for Island of Misfortune quest.
Koressia Fort contained a large stockpile of drachmae that Xenia needed stolen. The loss of the coffers would weaken the leader of Keos significantly.
A Chest Full of Drachmae
Related points of interest
Objectives of A Chest Full of Drachmae
1. Find and Acquire the Nation Chest
2. Quest Completed
Rewards: Epic XP, Legendary Drachmae (1575 + 1407 @ lvl 29), Black Axe (Epic Heavy Bladed)