Poul Anderson 
Merman’s Children [EPUB ebook] 

The last of the merfolk scour Earth for a new home to call their own The underwater city of Liri has thrived off the coast of Denmark for generations. But now, as Europe’s medieval age comes to a close, the efforts of zealous priests and the destructive ringing of church bells are causing the city to crumble. An ageless people who thrived apart from the cruelty of human existence on land, the merfolk are poetic speakers, loving and loyal, nearly impervious to death but with one great deficiency: They lack souls.   Their numbers dwindling, the merpeople scatter. Some abandon their home for the coast of Dalmatia in the Adriatic Sea, while others—the half-human, half-seaborn children of the great merfolk king Vanimen—decide to scout alien territory on land for adventure, treasure, and clues to their lost human heritage.