To add to the above, it's worth noting that the first series - entitled, as
ryano notes, 'The Black Adder' - was something of a false start, albeit an interesting one, rather akin to '
Star Trek: The Motion Picture'. In its favour, 'The Black Adder' was expensive and good-looking, with the addition of lots of location footage shot on
film in the snowbound wastes of
Northumberland.
Against it, it wasn't particularly funny (Ben Elton was not yet part of the writing team), and the 'group dynamic' had not yet been worked out - Edmund Blackadder was vain and pompous, but lacked any of the guile present in his later incarnations, Baldrick was a shrewd manipulator, and none of the other characters made much of an impression. Rowan Atkinson is generally known for playing vain, bumbling fools, and thus this characterisation should have worked - unfortunately, in a dramatic context it was impossible for an audience to root for a cringing buffoon, and thus the character was more annoying that amusing.
As with the BBC's own 'The Hitch-Hiker's Guide to the Galaxy' of two years before, the ratings weren't high enough to justify the prodigious expense. Somebody obviously had faith in the idea, however, as the programme was allowed to continue with major format changes - subsequent series were studio-bound, snappier, and used contemporary historical events as a means of satirising the present day, rather than as set-dressing. The title character became a canny manipulator, and much funnier because of it. 'Blackadder' eventually became a national institution and staple of satellite and cable tv marathons, running from 1983 to 1989 in bi-annual six-episode batches.
As with 'Monty Python's Flying Circus' and 'The Day Today', a certain caste of British society can reliably recite several entire scenes and many dozens of quotable lines. "I have a cunning plan", "A cluster of colourblind hedgehogs - in a bag", "I think the phrase rhymes with 'Clucking Bell'", and I must stop.