Patrick, if you read through the messages here, and some of the other threads, you will see that Robert Tannahill would be credited with the writing of the original. The modifications to change it were done anonymously. It's suggested that someone around the turn of the 20th century, perhaps an itinerant school teacher, taught it to kids in the schools in and around the Petpeswick area. There was one singer prior to Catherine who sang the song, but it definitely was Catherine who made it popular.