The story does not conflict with historical facts. Historical characters are presented in a way that seems possible. Details about everyday life such as clothing, housing, transportation, speech, social relationships, etc. are accurate. Characters are portrayed realistically and true to their time in history. Historial facts are a natural part of the story.
Illustrations provide accurate information.
Stereotypes are avoided. It is a well told story that is believable. Unless you are an experienced user, you should use a template. Avoid crowding too much text on a slide. Find a shorter way to say it.