This classic German fairy tale tells the story of a princess who befriends a frog after she accidentally drops her golden ball into a pond. The frog promises to retrieve the ball in exchange for her friendship. After the princess reluctantly agrees, the frog magically transforms into a handsome prince. They eventually marry
From Wikipedia
"The Frog Prince; or, Iron Henry" is a German fairy tale collected by the Brothers Grimm and published in 1812 in Grimm's Fairy Tales. Traditionally, it is the first story in their folktale collection. The tale is classified as Aarne-Thompson type 440.