Page "X Window System" Paragraph 121

Although X10 offered interesting and powerful functionality, it had become obvious that the X protocol could use a more hardware-neutral redesign before it became too widely deployed, but MIT alone would not have the resources available for such a complete redesign.

As it happened, DEC's Western Software Laboratory found itself between projects with an experienced team.

Smokey Wallace of DEC WSL and Jim Gettys proposed that DEC WSL build X11 and make it freely available under the same terms as X9 and X10.

This process started in May 1986, with the protocol finalized in August.

Alpha testing of the software started in February 1987, beta-testing in May ; the release of X11 finally occurred on 15 September 1987.