In the war to unite the planets, the Battle Of Serenity was among the most devastating and decisive. Located on Hera, the valley was considered a key position by both sides, and was bitterly fought over. The Independents, with sixteen brigades and twenty air-tank squads, held the valley against Alliance forces for almost two months, until superior numbers and a deep-flank strategy by General Richard Willkins ended the conflict.
It was the last large battle of the war and resulted in treaties being signed on what has historically come to be known as Unification Day or "U-Day" to those who actually celebrate it.
Using modern American troop counts, there would have been 72,200 browncoats at Serenity Valley, 10 men to a squad and 4,500+ men to a brigade. The browncoats suffered 68% losses, so 23,104 men would have lived.