[1] It was later translated to Norwegian as Gutten, Havfruen og Ridder Rød by Friis;[2] and into German as Der Knabe, die Meerfrau und Ritter Roth by Scandinavist Josef Calasanz Poestion [de].

[3] Later, author Andrew Lang included an English-language version in The Brown Fairy Book with the name The Mermaid and the Boy, in 1904.

They raised their son and when the youth was 16, the king and queen decided to have him leave home so the mermaid would not be able to find him when she came to collect on the promise.

The prince continued his adventure and arrived at a city where there lived a young princess who hated all men and would not permit one in her presence.

He agreed to do so, and told her if he did not return, she should play a violin on the seashore loudly enough to reach the bottom of the sea.

The princess brought the prince to the feast and challenged the Red Knight to turn himself into a lion, a bear, and a bee, at all three of which he failed.

In tale type ATU 316, the hero's father promises his unborn son to a water spirit, and they try to cheat her out of the deal until the boy is old enough.

[5][6] In tale type ATU 665, the hero helps some animals in distress and gains some of their body parts (e.g., fur, scales) as tokens that allow his transformation.

However, a false hero takes the credit for the deed, and is eventually unmasked when the princess asks him to prove he can shapeshift into animals.