The Tintavel Massacre was an event that changed the ways to fight wars.
Tintavel was within the Free Worlds League, but was captured by the Capellan Confederation during the Age of War. In 2412 a FWLM force invaded, intending to recapture the planet. The battle raged into urban areas and escalated until both sides employed various weapons of mass destruction, leading to over 300,000 causalities and forced the remaining population to abandon the planet.
The Capellan Chancellor Aleisha Liao recognized that one reason for the escalation of the battle were the only vague rules of engagement of this time. Those rules led to numerous similar situations on other worlds. On her behalf, representatives of all the major powers met on the planet of Ares and agreed on a treaty, known as the Ares Conventions, that defined a set of engagement rules. The intention was to prevent unnecessary loss of life in future conflicts.
- Era Digest: Age of War, p. 5, "Barbarism and Chivalry"
- Handbook: House Liao, p. 17, "Capellan Confederation Founding "