How to Use a Relative Pronoun to Add Information to a Sentence

Many British children who learn about Henry VIII at school know a short poem, which helps them remember the order of the Bible. Remember the order of Henry VIII's marriages and how they ended. Here we have our first example of a relative pronoun, which is who. And because we use who and this clause with commas to separate it from the rest of the sentence, this is like extra information we're adding here.