Following another jayhawk attack under jayhawk leader James H. Lane on the innocent people of Osceola, MO that resulted in all but 3 of the town’s 800 existing buildings being burned and 9 men executed, William Quantrill and his men began to plan a retaliation attack on the city of lawrence ks to send a message to the terroristic behavior of the jayhawks. Quantrill said his motivation for the attack was, "To plunder, and destroy the town in retaliation for Osceola." August 21st, 1863 was selected by the men as the target date.
With plans and organization underway, a makeshift prison used to house the female relatives of the men associated with Quantrill was made to purposely collapse on top of them. At the time there were at least 10 women and girls, all under the age of 20, imprisoned there and 4 of the girls were killed in the collapse with many others receiving life altering injuries. The retaliators motivation for revenge was thusly greatly heightened.
Between 300 to 400 men arrived in Lawrence on the morning of August 21st, and in the next four hours greeted the citizens:
http://upload.wikimedia.org/wikipedia/commons/9/9b/Battle_of_Lawrence.png
When they were done, Lawrence was substantially re-decorated.
http://upload.wikimedia.org/wikipedia/commons/7/7f/Lawrence_massacre_ruins.jpg
While less than 2 weeks later the jayhawkers re-organized with their sights set on destroying Westport in a similar fashion, they were turned back thanks to no longer having the strength to continue their terroristic ways from the depleted manpower of Quantrill's successful raid. As the staunchly pro-Union George Caleb Bingham would later proclaim, “the real culprits behind most of the depredations committed in western Missouri and eastern Kansas were not the pro-Confederate bushwhackers, but rather pro-Union Jayhawkers and "Red Legs.” Thankfully, shortly thereafter the jayhawks lost their leader James Henry Lane when he shot himself in the head and committed suicide.
But jayhawks are like cockroaches, and the people of kansas identify strongly with the terroristic actions and take great pride in the senseless suffering they enacted upon Missourians. So when the university of kansas organized a football team less than 30 years later to establish a sports rivalry with the University of Missouri, they saw only fitting to rekindle the jayhawk name to symbolize themselves and antagonize the descendants of those recently murdered...even taking to wearing ‘Red Legs’ when the two opponents met on the field of play.
It took nearly 150 years for the good people of Missouri to completely separate themselves from the jayhawkers.