KU's world famous Rock Chalk Chant evolved from a cheer that a chemistry professor, E.H.S. Bailey, created for the KU science club in 1886.
Bailey's version was "Rah, Rah, Jayhawk, KU" repeated three times. The rahs were later replaced by "Rock Chalk," a transposition of chalk rock, the name for the limestone outcropping found on Mount Oread, site of the Lawrence campus.
The cheer became known worldwide. Teddy Roosevelt pronounced it the greatest college chant he'd ever heard. Legend has it that troops used the chant when fighting in the Philippines in 1899, in the Boxer Rebellion in China, and in World War II. At the Olympic games in 1920, the King of Belgium asked for a typical American college yell. The assembled athletes agreed on KU's Rock Chalk and rendered it for His Majesty.
You can hear the chant here.