Deadwood (TV series) is celebrated as being one of the most foulmouthed shows on cable TV.
This was a conscious decision by the scriptwriters, to convey the impression that 1870s foul language would have had on its contemporaries. Because using actual 1870s foul language (which was blasphemous rather than scatological) would have sounded so anodyne to modern ears, it would have been laughable.
Good summary thereof at Deadwood (TV series) – Wikipedia
The use of damn, which Rynnah Lim mention, is one such blasphemous word: it used to be censored in print, the way fuck often still is. Bloody also originates in blasphemy (God’s blood).
The inflation happened within living memory: Eliza Doolitle scandalously said “not bloody likely” in the 1912 premiere of Pygmalion. By the time of My Fair Lady in 1964, the scandalous phrase had to be updated (with some exoticisation of Cockney) to “move your bloomin’ arse”. Fifty more years on, it would have to involve at least one fucking to have the same effect.