The first Gallente-Caldari War broke out nearly two centuries ago when the Caldari State seceded from the Gallente Federation. The conflict dragged on for almost a century and ultimately ended in a stalemate, concluding with a peace treaty signed by both sides.
Lore
In 23155 AD, the Gallente discovered several secret Caldari colonies. Because the colonies had not been established according to Federation law, the Gallente attempted to penalize the Caldari. This eventually escalated, with the Caldari withdrawing from the Federation. A Caldari terrorist cell sabotaged a dome of the underwater Gallente city Nouvelle Rouvenor, killing half a million people.
A fascist government took power in the Federation following the attack, which began military operations against the Caldari. As the Caldari evacuated their homeworld, the Federation planned a large assault on the planet. In order to delay them, a detachment of the Caldari fleet attacked the Federation Navy, and engaged in hit-and-run strikes. When the fleet was too damaged to continue, they ran one last suicide mission, crashing their carrier into Gallente Prime, an act which killed two million people in the city of Hueromont.
The two sides fought to a protracted draw, with each side gaining temporary advantages, only to see them eventually vanish. The Caldari developed fighters, only for the Gallente to counter with drone technology. The Caldari then gained the capsule from the Jove, while both nations developed the Titan. The two sides fought the second-largest battle in history at the Battle of Iyen-Oursta, which inflicted heavy casualties to both.
After nearly a century of conflict, both sides had become exhausted by the simmering war. They eventually signed a peace treaty in 23248 AD, after the Gallente Senator Aidonis Elabon founded CONCORD, and convinced both the Amarr Empire and Jove to join.