Title says it all: when was BSD-2 published? Everywhere I've looked has no information about when the BSD-2 "Simplified" license was published.
The earliest date known so far is Feb 6, 1997.
Note that there is unlikely anything official and formal with the first use of this license. Someone at some point just took its knife to cut the 3rd and 4th clauses from the BSD original text (e.g. "four clauses"). The trick is to find who did it first and when. Here is some of my research towards this going progressively backwards in time:
This commit from December 31st, 2003 shows the license appearing as the top-level primary license for the FreeBSD Project and is referenced as the "compilation copyright" in the commit comment:
Update the COPYRIGHT file to include FreeBSD's compilation copyright
But this "two clause" BSD license as used in FreeBSD today as the top level license appeared well after the fourth clause of the "four clause" BSD (the advertizing clause) was "rescinded" by the UC Regents on July 22, 1999. Before that the fourth clause was still applying.
And the wayback machine tells us that as early as April 29 1999 this BSD variant was already in use on the main project web site.
And this commit on Sep 26, 1998 shows it was used already at this stage for specific subsets of the code.
And a tad before this commit shows that on Feb 6, 1997 it was already there used for some
It may have been in use before and elsewhere though.... I have asked the committers for details ... and I will continue to dig now and then and update the answer.