The world's oldest song is a Sumerian hymn.

In the early 1950s, archaeologists discovered clay tablets dating back to 1400 BC. The tablets were found in the ancient city of Ugarit, in what is now Syria, and were written in cuneiform in the Hurrian language. After research, it turned out that this was the first piece of music ever discovered, and it contained a 3,400-year-old religious hymn.
Anna Clymer, a professor of Assyriology at the University of California, Berkeley, provided a translation of this text in 1972, and adapted musical notation to it.

Richard Fink, in a 1988 paper, claimed that the current 7-note scale dates back to this Sumerian hymn. This research contradicts the popular belief that the current 7-note scale dates back to ancient Greece.

Clymer's colleague Richard Crocker says the new discovery "revolutionizes all beliefs about the origins of Western music."