Battle of Titan was the beginning of the Pilgrim War.
The militant faction of Pilgrims controling the Pilgrim Alliance was not satisfied with Terrans reaching their interstellar sphere, and decided to cripple their colonization efforts by cutting their incursion at the source. The Alliance assembled a fleet at Beacon and mounted a massive assault to destroy the station in a quick, surgical assault, attack Earth, expecting a primitive and unprepared target.
On 2631.244, the fleet jumped into the Sol System, but the Confederation was proved to be surprisingly stron and rich with significant defensive resources. Intense fighting around Saturn lasted for 3 days, Titan remained intact and the Pilgrims were forced to retreat.
After the Battle, the Confed offered a new round of negotiations, but the Alliance ignored it. Instead they proceeded to aggressive guerilla action in Confed space.