HTML 1.0 had only 20 elements that can be used as a markup language. It was the first time it became available to public use. (jan 1, 1991 – jan 1, 1994)
Description:
https://blog.rackspace.com/internet-history-html-evolutionAdded to timeline:
Date:
jan 1, 1991
jan 1, 1994
~ 3 years