From 1855 to 1858 , Kansas Territory experienced extensive violence and some open battles . This period , known as " Bleeding Kansas " or " the Border Wars " , directly presaged the American Civil War . The major incidents of Bleeding Kansas include the Wakarusa War , the Sacking of Lawrence , the Pottawatomie massacre , the Battle of Black Jack , the Battle of Osawatomie , and the Marais des Cygnes massacre
Pottawatomie massacre
Pottawatomie massacre
History of Kansas