I don't believe there was ever a time someone would know everything simply because different geographical location have different flora and fauna special to that region. For example, no one outside of the Americas knew about corn until the 15th century, and no one in the Americas knew about rice until after that. By exclusion, no one knows everything.

I just finished reading [Thomas Young's](http://en.m.wikipedia.org/wiki/Thomas_Young_(scientist)) biography aptly titled *The Last Man Who Knew Everything *. I suppose if you narrow "everything" to orthodox, academic knowledge available to one's culture, then there are several 18th and 19th century polymaths who come close. Young is my favorite. After the advent of mass communication (telegraph, radio, Internet) the possibility of anyone appearing to have knowledge of everything rapidly declines.

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