History of XML

1969: Ed Mosher, Ray Lorie and Charles F. Goldfarb invent GML which can stand for either Generalized Markup Language or Goldfarb, Mosher, Lorie.

GML evolved into SGML (standard generalized markup language) [ISO standard 1986].

1996: W3C started to define a markup language that combined the flexibility of SGML with the widespread acceptance of HTML. A goal was to make this new language easier than SGML.

1998, February: W3C's XML standard 1.0. (Here's the annotated xml specification).

The first use for XML was JUMBO (a browser for CML [chemical markup language] by Peter Murray-Rust) CML was sort of the HTML for molecules.

Other uses are MathML.
See also Formulator.