Hans Christian Andersen was a 19th century Danish writer of fables, and children's fairy tales.
Among his works was the fable of The Little Mermaid, which Jadzia Dax told to the Elaysian cartographer Melora Pazlar in 2370, pointing out similarities between the situations of the little mermaid and the Elaysian Melora (specifically, her desire to change her body permanently in order to effectively operate in a different environment than her native one). (DS9: "Melora")
According to the Star Trek Encyclopedia, 4th ed., vol. 1, p. 483, the birth and death years of Hans Christian Andersen were 1805 and 1875, respectively.