The first documented version of HTTP was HTTP V0.9 (1991) has only GET: http://www.w3.org/pub/WWW/Protocols/HTTP/AsImplemented.html

Basic HTTP as defined in 1992 had GET, PUT, HEAD, POST, LINK, TEXTSEARCH, CHECKIN, etc.: http://www.w3.org/Protocols/HTTP/Methods.html

More generic info: http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol

I believe they originally come from the libwww-perl project? According to wikipedia it was first released with perl 4.0036, which was in Februrary 1993, but I can't find out if it included GET and HEAD etc already then...

They're mentioned in a February 1996 changelog entry for libwww-perl, so at least 19 years.

RFC 1945 dated may 1996 mentions GET and POST methods

http://www.rfc-base.org/txt/rfc-1945.txt

HTTP has been in use by the World-Wide Web global information initiative since 1990. This specification reflects common usage of the protocol referred to as "HTTP/1.0".