Sometimes they don't actually know. History isn't always written accurately. Or sometimes, not even at all.
Also, sometimes what actually happened isn't considered a good story. So, directors change the story to make it more like what they think people want to watch.
[Henrik]
I'm not surprised.
Your siblings do still love each other, you know. Just, being together for as long as they have...they have a lot of unresolved issues between them.