He was supported by the "Secret Six", which included the former vice president of the American Peace Society, Gerrit Smith, and this man met with other supporters in Canada to form the provisional Chatham Constitution.  
One of this man's supporters had earlier led an attempt to rescue Anthony Burns, while another, Franklin B. Sanborn, had been a student of Emerson.  He was supported by the "Secret Six", which included the former vice president of the American Peace Society, Gerrit Smith, and this man met with other supporters in Canada to form the provisional Chatham Constitution.  He was involved in the Pottawatomie Killings during Bleeding Kansas, and he wrote the "Vindication of the Invasion" before leading an expedition that began on his rented farm in Maryland.  For 10 points, identify this man who led a slave revolt in Harper's Fairy.
One of this man's supporters had earlier led an attempt to rescue Anthony Burns, while another, Franklin B. Sanborn, had been a student of Emerson.  
John {Brown}