Al Swearengen's line, "Welcome to Deadwood ... can be combative," to Seth Bullock's family after his fight in the street with Bullock, was semi-improvised by Ian McShane. Writer David Milch came up with the "Welcome to Deadwood" line on the spot during the shoot. He added "can be combative" to McShane right before the take as instruction for how to deliver the line. McShane thought the whole thing worked.
David Milch originally had planned for Martha Bullock (Anna Gunn) to arrive in Deadwood midway through the first season, but this was repeatedly delayed because Milch kept introducing new storylines and material for peripheral characters.
The title comes from a famous saying (most frequently attributed to Napoleon) that history is a lie agreed upon.
Sarah Paulson and Ian McShane were also in American Horror Story: Asylum (2012) together.
Anna Gunn's (Martha Bullock) first episode on Deadwood. She plays the wife of the top billed, Timothy Olyphant (Seth Bullock). She later played the wife of another top billed actor on a show, Brian Cranston, on Breaking Bad. Jim Beaver (Ellsworth) also worked on Breaking Bad.