Corrected entry: In 'Black Adder's Christmas Carol': It is obvious that all the money we see is fake, it is the wrong shape to be real money and is blank on one side.
Corrected entry: In Back and Forth, Blackadder runs into Shakespeare, and he picks up a copy of Macbeth. But Macbeth was written during the time of James I.
Correction: The whole point of this show is that Blackadder and Baldrick are blundering about with a time machine, changing history as they go. The timeline of Shakespeare's literary output was just one of those changed.
Corrected entry: In the Christmas Carol, Queen Elizabeth claims she cannot reverse a death warrant. But in series 2, episode "Potatoe" Walter Raleigh is let off, and in episode 2-2, "Head", she also gives a pardon from death sentence.
Correction: And during the entire series she changes her mind on numerous different issues depending on what mood she is in that day, or even that moment. One of the aspects of her character is the fact that she is inconsistent and changes her mind with child like frequency, as and when the feeling takes her. So hardly a mistake, just a character trait.
Corrected entry: In the first series the lead character's name was written as two words, "The Black Adder" (well, technically three words), and in subsequent series it was written as one word, "Blackadder". This is not a mistake, however; this is the normal way that languages evolve. The name evolved from the two word pseudonym used by Prince Edmund into the one word name used by his descendants.
Correction: This is not valid trivia. It's obvious to anyone who watches the show, or even just reads the title.
Corrected entry: In 'Blackadder back and Forth', we hear George ask Blackadder for a pair of old underpants so that he'll pay him the £10,000. However, after Blackadder returns from the past the first (and second) times, he has not got the underpants, so why is George giving him the money?
Correction: I suspect it's because they asked Blackadder to prove his time machine worked, by gathering the things they asked for. Two out of 3 isn't bad, so George accepts that the machine works.
Correction: As money was in those days. See http://www.wirksworth.org.uk/X522.htm, amongst others.