Heikki wrote a nice post about how the Midgard project got started some ten years ago. Bergie's comment also a briefly mentions the SusiSGML system that we used before Midgard.
SusiSGML was a custom SGML vocabulary with a set of DSSSL stylesheets that we used to cook the structured content into HTML with styling based on tables and all that stuff one used before the CSS revolution.
Architecturally SusiSGML was pretty much like early versions of Apache Cocoon, only with SGML and DSSSL instead of XML and XSL. Had we been at it a few years later, Midgard might have been based on Cocoon. :-)