Some of you have probably read Hackers by Steven Levy. The last section is about Richard Stallman described as 'the last of the true hackers'. This contains what appears to be Stallman's account of what he saw as the breakdown of the AI Lab caused by the foundation of Symbolics.
I somehow recently came across this post by Dan Weinreb, one of the founders of Symbolics, with a rather different account...
You really have to read the comments as well, which contain comments by a number of other people involved agreeing with the account and comments by people saying 'but there are all these other references agreeing with Stallman's account' to which the reply is inevitably 'yes, but the widely disseminated story is Stallman's, a bunch of secondary sources parroting this story doesn't really prove anything'.
There are some other interesting posts about Symbolics on Weinreb's blog - http://danweinreb.org/blog/category/sym