According to Dorothy Dinnerstein's book "The Mermaid and the Minotaur," human-animal hybrids, such as mermaids, symbolized how humans were both distinct from and similar to animals. In art and literature, mermaids have been portrayed as deadly seductresses, entrancing men with their beauty and tempting them to their deaths, symbolizing both a fear of female sexuality and a morality lesson on forbidden fruit.
In ancient Rome, the church used mermaids as icons of harlots and whores, portraying the evils of lust. They reappeared during the Medieval Age, with their fish tails evocative of the scales of serpents, creating a link between mermaids and original sin. In literature, stories of mermaids falling in love with humans and searching for souls have long been popular, and have been used to express dissatisfaction with the church and criticize society's shortcomings.
The most famous mermaid, immortalized in the works of Hans Christian Andersen's "Little Mermaid," represents the unification of these evolving themes. As a mermaid, the main character is inherently soulless; her quest for a soul is represented by her quest for her wealthy human lover. When he spurns her, the mermaid's fortitude and strength nevertheless allow her suffering to end as she is elevated into martyrdom. In the story, the mermaid represents doomed passion and is a subverted femme fatale who dies tragically and beautifully.