ERC was originally written by Alexander L. Belikoff and Sergey Berezin. They stopped development around December 1999. Their last released version was ERC 2.0.
P.S.: If one of the original developers of ERC reads this, we'd like to receive additional information for this file and hear comments in general.
In June 2001, Mario Lang and Alex Schroeder took over development and created a ERC Project at http://sourceforge.net/projects/erc.
In reaction to a mail about the new ERC development effort, Sergey Berezin said, “First of all, I'm glad that my version of ERC is being used out there. The thing is, I do not have free time and enough incentive anymore to work on ERC, so I would be happy if you guys take over the project entirely.”
So we happily hacked away on ERC, and soon after (September 2001) released the next "stable" version, 2.1.
Most of the development of the new ERC happened on #emacs on irc.openprojects.net. Over time, many people contributed code, ideas, bugfixes, and a lot of alpha/beta/gamma testing.
See the CREDITS file for a list of contributors.
ERC 3.0 was released.
ERC 4.0 was released.
ERC 5.0 was released. Michael Olson became the release manager and eventually the maintainer.
After some discussion between him and the Emacs developers, it was decided to include ERC in Emacs.
ERC 5.1 was released. It was subsequently included in Emacs 22.
ERC became an official GNU project, and development moved to http://sv.gnu.org/projects/erc. We switched to using GNU Arch as our revision control system. Our mailing list address changed as well.
We switched to using git for our version control system.
Since about 2009, ERC is no longer developed as a separate project, but is maintained as part of Emacs.