This is one of my childhood shows. I had read all of the books and I used to watch horrible histories after primary school every day. The original cast (first 5 seasons I believe) are amazing and hilarious, they really made the show. The jokes always landed, the songs were great, I learnt so many facts from it. I still watch it to this day! However, there was a cast change from season 6 onwards. They don't work as well as the old cast at all, and the show simply isn't good anymore, it's lost its spark. I'd say if you want to watch the show just watch seasons 1-5 and call it a day. If you want to see more of the actors' works, I heavily reccomend Ghosts and Yonderland.