The details on this one is pretty sketchy, so I'm working on my memory here. Staff, please edit and correct if need be. Also, please add the joining dates of staff if possible.

July 10th (or so, 2004):

I (replicated) just finished watching Shingetsukan Tsukihime. It rocked. I know I was a year or so late (thanks, bio ;p), but I was busy with life (yeah, *cough*) so I only got around to watching it then. I needed more.

I sleuthed around for information, and then I stumbled upon the original game. I looked for English translations. Found none. So then I complained in #Manga-Sketchbook about the lack of a translation for Tsukihime. It was merely coincidence that AstCd2 and dmpk2k were around and sympathized with me. "Hell," I went, "why don't we start our own project?"

I had (rudimentary) coding skills, dmpk2k had some and a good grasp of the English language, while AstCd2 translated manga. I had no idea how the name Mirror Moon came into being, but that was the name.

July 12, 2004:

dmpk2k regged mirrormoon.org.
I started looking for ways to decrypt the script file for starters, and I stumbled upon ONScripter, an open-source NScripter emulator. In one of the source files for ONScripter, I found the magical line that decodes the file: ^ 0x84. Of course, then I found out that there was a program that did that for you (nsasomething?), so it was rather useless. But the discovery of ONScripter was very important. It was open-source, so I could hack it into displaying single-byte text.

August 3, 2004:

First correspondence with Ogapee, author of ONScripter. I have completed the basic English hack at this point and was asking him how to fix the garbled menus.

August 30, 2004:

First contact with Revolve (mentioned in email to Ogapee).

September 9, 2004:

Ogapee's support of 1-byte characters within all code arguments, extremely important for the select code.

A lot of emails going back and forth as I submitted bug reports and possible patches to Ogapee. He's a great and patient man :)

January 18, 2005:

Submission of my ugly word-wrap patch. I didn't know C++ back then.

April 1, 2006:

Fate/stay Night was officially announced as our second project.

That's the very concise history so far... please add more information if you have it.