The California Historical Society (founded in 1871) was officially recognized as a symbol of California in 1979. The Historical Society's mission is:

"...to engage the public’s interest and participation in collecting, preserving, and presenting art, artifacts, and written materials relevant to the history of California and to support historical research, publication, and educational activities."

The Historical Society contains a collection of manuscripts, posters, printed ephemera, books, maps, and pamphlets, and features works by photographers Eadweard Muybridge and Ansel Adams. The Society also publishes an academic journal: "California History."

Source:

California Historical Society: official website

Links:

Cultural Symbols - 50 states