* Music Charts: These weren't established until the early 20th century, so there's no objective record of what songs were most popular before then.
* Commercial Success: This depends on what constitutes a "hit" – did it need to be the best-selling song of the time, or just popular enough to be recognized?
* Definition of "Single": This term evolved, so what was a single in one era might have been a different format later on.
That being said, there are some early contenders for the title of first hit single:
* "In the Shade of the Old Apple Tree" (1905): This song by the American composer and singer, Harry Lauder, was a massive hit and sold over a million copies. It's considered the first "million-selling" song.
* "Alexander's Ragtime Band" (1911): This piece by Irving Berlin was incredibly popular and was even used in a popular silent film.
* "My Wild Irish Rose" (1898): This ballad by Chauncey Olcott achieved wide recognition and remains popular today.
Ultimately, while we can't pinpoint the first ever hit single with absolute certainty, these early examples demonstrate the beginnings of a musical phenomenon that would define the music industry for decades to come.