The show is similar to Game of Thrones but grounded in history. But I've not taken the time yet to see accurate and aligned with history the Vikings might be. I compare it to Game of Thrones in that the main star of the television show, Ragnar, has at least six boys. One son killed the other son who was mocking him. Another son dies in a battle. The other four sons end up battling each other or sometimes working together against the other sons. In the show, different people become king of the different places. They die and then the sons or other people become king, similar to what you see in Game of Thrones but without the dragons. But they do reference dragons in the same breath that they mention the myth of Thor and other gods.