==Khan Academy== 
 Information sourced to Khan Academy's SmARThistory was removed here with a note that it "looked a bit dodgy". I've looked at as well. (Note: I did not add this source originally. This material was added here.) I don't think the source looks dodgy; it's cited to reputable project (SmARThistory) within a reputable website (Khan Academy). The lecture is by Beth Harris (former Director of Digital Learning at The Museum of Modern Art) and Steven Zucker (former chair of History of Art and Design at Pratt Institute and of the art history department at SUNY). Both of these professors have extensive publishing histories. Seems thoroughly reliable to me. I've restored it.