the battle of osawatomie took place on saturday, august 30, 1856 in the town of osawatomie, kansas. john brown and about 40 men tried to defend the town against an attack by about 250–300 border ruffians. the missouri ruffians were led by john w. reid. the attack began early in the morning when frederick brown, son of john brown, was shot and killed outside of the town. this alerted john brown and others who tried to defend the town. but heavy casualties forced brown and the other abolitionists back across the nearby river. the town was looted and burned but brown was not pursued. this was one of many clashes between pro-slavery and free-staters during the period known as bleeding kansas.