Why was Uncle Tom's Cabin created?

Not mine the work, but thine―Oh! heavenly messengers of peace and freedom! my brothers and my sisters―

Uncle Tom's Cabin was a partnership creation. 

I gave my time, my fullest sympathy, I made a study of southern scenes and character, and yet I could never have put the spirit into the book, which still lives if I had not been dominated by a superior power.My characters talked for themselves―they dominated me―thank God―these strange evangels have done a portion of the great work.