Did anyone know this before?

It is just a ファン fiction, although it could be considered as partially true.

In my fandom, the Queens aren't the ones who are related; but the クイーン of Corona and the King of Arendelle are. They have much もっと見る in common. あなた may find an 記事 または post in a アナと雪の女王 fandom site または in Tumblr

In some other stories, they claim that Ariel's sunken ship may also be the sunken ship of the King and クイーン of Arendelle. It could be true since Arendelle is located in Norway, and The Little Mermaid could originate from Denmark.

If あなた take the Coronation Cameo Theory of the fandom, the ship may have passed によって Denmark on it's way to the Kingdom of Corona in Germany. It may have sunk there.

It's funny on how everything is connected in most ディズニー Princess movies.

Here's a link to better explain the answer:
link

Uh.. I do not think so... I think Anna, Rapunzel and Elsa are just friends

no i didn't

that's true

Yeah, I've heard of things like this before. It could be true.

It's an Easter egg, planted from the animators to 表示する the connection between 塔の上のラプンツェル and Frozen, so yes, it is true.