According to MLA format do I have to site factual information if I did not look it up, I just knew it?

Read the sentence below about the chicago fire of 1871. schaffer told someone else to strike the wrong alarm box and that caused a miscommunication during the chicago fire of 1871. which revision is the best example of adding concrete details? schaffer told another person in his office to sound the wrong alarm and that caused a big miscommunication during the chicago fire. schaffer told his assistant to strike the wrong alarm box and that caused a miscommunication during the massive chicago fire of 1871. schaffer mistakenly told his assistant to strike alarm box 342 instead of the correct box and that caused a miscommunication during a fire in chicago. schaffer mistakenly told his assistant to strike alarm box 342, and as a result, firefighters were directed to an incorrect location during the chicago fire of 1871.