Larry Sanger IS a co-founder of Wikipedia:

“Wales and Sanger created the first Nupedia wiki on January 10, 2001. The initial purpose was to get the public to add entries that would then be “fed into the Nupedia process” of authorization. Most of Nupedia’s expert volunteers, however, wanted nothing to do with this, so Sanger decided to launch a separate site called “Wikipedia.” Neither Sanger nor Wales looked on Wikipedia as anything more than a lark. This is evident in Sanger’s flip announcement of Wikipedia to the Nupedia discussion list. “Humor me,” he wrote. “Go there and add a little article. It will take all of five or ten minutes.” And, to Sanger’s surprise, go they did. Within a few days, Wikipedia outstripped Nupedia in terms of quantity, if not quality, and a small community developed. In late January, Sanger created a Wikipedia discussion list (Wikipedia-L) to facilitate discussion of the project.”