In his book, Chasing the Rising Sun, Ted Antony explains how the song came to both musicians at a time when information was still hard to move from town to town, reaching the conclusion that, originally, the song was transmitted orally thanks to the railroad. Ashley traveled around in the Appalachian region in the 1920s. Back then, medicine shows were extremely popular. These shows were basically people selling “medical” remedies (which were usually nothing but alcohol mixed with sugar), while singers performed for the people who gathered around them. The singers made money from these performances, of course, while the "doctors" used the songs as jingles that people could remember and associate with their products. Another theory is that in the previous decades, the railway was still being built, so workers sang folk songs as they worked, which would explain how the song traveled across the country. [links]