The Mysterious History of the MIT License

Red Hat technology evangelist Gordon Haff explains why it's hard to say exactly when the MIT license created. Citing input from both Jim Gettys (author of the original X Window System) and Keith Packard (a senior member on the X Windows team), he writes that 'The best single answer is probably 1987. But the complete story is more complicated and even a little mysterious.'
An anonymous reader quotes his article at OpenSource.com, which begins with the X Window System at MIT's 'Project Athena' (first launched in 1983):

X was originally under a proprietary license but, according to Packard, what we would now call an open source license was added to X version 6 in 1985... According to Gettys, 'Distributing X under license became enough of a pain that I argued we should just give it away.' However, it turned out that just placing it into the public domain wasn't an option. 'IBM would not touch public domain code (anything without a specific license). We went to the MIT lawyers to craft text to explicitly make it available for any purpose. I think Jerry Saltzer probably did the text with them. I remember approving of the result,' Gettys added.

There's some ambiguity about when exactly the early license language stabilized; as Gettys writes, 'we weren't very consistent on wording.' However, the license that Packard indicates was added to X Version 6 in 1985 appears to have persisted through X Version 11, Release 5. A later version of the license language seems to have been introduced in X Version 11, Release 6 in 1994... But the story doesn't end there. If you look at the license used for X11 and the approved MIT License at the Open Source Initiative (OSI), they're not the same. Similar in spirit, but significantly different in the words used.
The 'modern' MIT License is the same as the license used for the Expat XML parser library beginning in about 1998. The MIT License using this text was part of the first group of licenses approved by the OSI in 1999. What's peculiar is that, although the OSI described it as 'The MIT license (sometimes called called [sic] the 'X Consortium license'),' it is not in fact the same as the X Consortium License. How and why this shift happened -- and even if it happened by accident -- is unknown. But it's clear that by 1999, the approved version of the MIT License, as documented by the OSI, used language different from the X Consortium License.

He points out that to this day, this is why 'some, including the Free Software Foundation,' avoid the term 'MIT License' altogether -- 'given that it can refer to several related, but different, licenses.'

Read more of this story at Slashdot.