Bas-relief above the door

The legend of the bas - relief reads:

In the 18th century, one of the Swedish merchant ships was already on its way home, when a calm overtook them in the Baltic Sea. The ship did not move for three days. Then the navigator threw a coin into the sea to call the sea lords to help them. A few minutes later he saw a mermaid in the water.

She asked for a favor, a favor, in return for a fair wind. The navigator agreed. The contract was such that the navigator would have to deliver a letter to Mr. Mons, who lives at the address Västerlånggatan 24 in Stockholm, and without delay, as soon as he set foot on the ground.

The free wind brought the ship into the bay of Stockholm, but the navigator did not have time to leave right away, as it was necessary to moor the ship properly. After 2 days, he came to the address indicated by the mermaid. The door was opened to him by an old lady who said in surprise that Mr. Mons was their cat.

She kindly invited the navigator for a cup of coffee. Imagine their surprise when her cat ran up to the sailor and pulled the letter out of his hands and began to read it in his cat language. After crying, he shouted at the navigator, "what was he told to bring as soon as he stepped on the ground," and then attacked him and scratched him to death!

After that, the desperate cat jumped out through the doorway and jumped onto the bas-relief above the door and remained there as part of it.