Origins of the Stanford NLP Group: 1999–2003
Christopher Manning was hired and came to Stanford for Fall 1999, becoming an Assistant Professor filling a newly created joint faculty position in Linguistics and Computer Science. Here are some early photos of Chris at Stanford from the Fall 1999 CS Department Retreat taken by Héctor García-Molina.

Christopher Manning with Daphne Koller

Chris, then CS department chair Jean-Claude Latombe, department manager Peche Turner, and Professor Héctor García-Molina
1999–2001
The first two Stanford NLP PhD students were Kristina Toutanova and then Dan Klein.
Kristina Toutanova
Dan Klein
2001–2003
The next PhD students were Sep Kamvar, Roger Levy, Teg Grenager, and then Jenny Finkel. (As usual, there then start to be some more complicated situations: Teg later dropped out and, actually, Jenny was an MS CS student during this period, but later a PhD student).
Sep Kamvar
Roger Levy
Teg Grenager
Jenny Finkel
Other students and visiting faculty around the Stanford NLP Group during these early years were: Mike Jahr, Tolga Ilhan, Mark Chavira, Kristen Parton, Joseph Smarr, Huy Nguyen, Andrea Tompa, Miler Lee, Jim McFadden, Cindi Thompson, Jeannette Pettibone, and Iddo Lev.
It’s not completely clear when there was first something called “The Stanford NLP Group”, but it definitely came into existence in the year 2000. The first save of the group’s website by the Internet Archive is from 2000-10-29. Here’s what the original page looked like:
Earliest save of the Stanford NLP Group web page in the Internet Archive