The last statement is the closest to what I have read. Rag time music derives from the banjo. It is the piano imitating the banjo. Somebody also mentioned the cakewalk. The popularity of the cakewalk highly contributed to the popularity of Rag time and vise versa. Rag time came in and out of vogue a few timees last century. Scott Joplin died pretty poor and his wife had to turn their NY home into a brothel in there later years. I think Maple Leaf Rag is considered the quintessential Rag time tune, written by Scott Joplin somewhere in Missouri at the turn of the century. A lot of songs are titled rags that wouldn't fit any academic definition because they were just calling everthing a rag for a while.