What really happened in Deadwood?

I'm a serious fan of the hit series Deadwood. And that's saying something, given that I watch about two hours of TV a week. The show is a multi-layered drama based upon real events that transpired in the late nineteenth century near Deadwood, South Dakota. The town erupted as gold fever infected the region, which signalled prospectors, charlatans, officials, hoods, and every combination thereof to attempt to take a piece of the action.

And if there's a better actor on the planet than Ian McShane, pictured above, I haven't seen him.

In any event, I just happened upon a site that distinguishes the historical from the fictional in this outstanding series:

What really happened in Deadwood?