In March 1855, abolitionists Rev. Samuel Adair and his wife Florella settled in a cabin near Osawatomie to serve as missionaries to the community. Florella's half-brother, John Brown came to "Bleeding Kansas" later the same year with a wagon of guns in order to help fight the pro slavery forces like his five sons, who were already living in another community in the area. Brown then came to Osawatomie to visit the Adairs and fight pro slavery forces there. By 1856, having established himself as a leader of free state guerillas, Brown made Osawatomie and the Adair cabin his base. In a raid in May 1856, Brown killed five pro slavery men along Pottawatomie Creek near the current town of Lane, Kansas. This was then referred to as the "Pottawatomie massacre", which inflamed the fighting throughout the Kansas Territory. The second and main Battle of Osawatomie took place on August 30, 1856. Osawatomie played a key role throughout the Civil War, serving as a center for Jayhawker activity.