To be a Disney Princess, one has to be a human/hybrid female. Their films have to be popular. They must be kind to all creatures. They all can sing. One does not have to be of royalty to be considered a Disney Princess, but instead have the recognition of a princess.
Merida is the only Disney Princess to not be from a Disney Canon, but instead from a Pixar film. Having said that, she also broke several Disney Princess traditions, being the only Disney Princess to have no love interest and does not sing a full song (but she did sing a small song when she was a child).
There is such a thing as Unofficial Disney Princesses. It consists of all the Disney heroines, but the Walt Disney Company never acknowledges such franchise.
In 2013, Disney redesigned all the Disney Princesses into sparkly costumes, which causes controversies.
Snow White Snow White is a 14-year-old princess by birth. She was the target of her evil stepmother, the Evil Queen, who tried to kill her due to jealousy. However, she was eventually saved by true love's kiss of her prince.
Cinderella is a 19- year-old woman of an aristorcratic family. After her father died, she was abused by her stepfamily and turned her into a servant. One day, the prince of the kingdom had a ball to find his true love. With magic from the fairy godmother, Cinderella found her happy ending.
Aurora is a 16 year-old princess who was disguised as a peasant to protect herself from the evil witch Maleficent. One day, she fell in love with Pince Philip, her unknown betroth. But Maleficent put her to sleep, and it's Philip's turn and the three good fairies to wake her up.
Ariel is a 16-year-old mermaid princess who dreamed to be on land. One day, she fell in love with a human prince and seeked help from the sea witch Ursula to turn her into human. She had three days to make the prince fall in love with her, but the evil Ursula used all her powers to stop Ariel with a goal of conquering the seven seas.
Belle is a smart 17-year-old girl who dreamed of adventure. The town hunk, Gaston, wanted her for a wife, but she knew better to stay away from him. One day, she saved her father from a Beast's castle and eventually fell for him. When the last magical rose petal fell, her prince turned into a human prince as they lived happily ever after.
Jasmine was a spoiled 16-year-old Arabian princess who yearned to get away from her castle. One day, she sneaked out and met Aladdin. But Jafar the Sultan's advisor wanted her hand for marriage in order to become king. She rejected and chose Aladdin instead.
Pocahontas was a 18-year-old Powhatan princess who loved adventure. One day, she fell in love with a European man named John Smith, transcending racial boundaries. This caused a war between the Indian and the English. However, through all the harships, John Smith and Pocahontas had to separate in order to keep John Smith alive. Years later, she eventually fell in love with John Rolfe, another English man.
Mulan was a 16-year-old Chinese girl. In order to save her father, she broke all traditions and disguised as a soldier and intelligently fought off the Huns. She was regarded as a hero of China and the emperor graced her with honor.
Tiana was a 18-year-old girl who worked very hard to have her own restaurant. However, because of her skin color, it was a difficult challenge. Tiana decided to take a shortcut and kissed a frog prince, turning herself into a frog in the process. On their journey to unravel the curse, Tiana fell in love with the prince, but had to struggle through Dr. Facilier in order to reach her dreams.
18-year-old Princess Rapunzel had a very long magical hair that could heal anything. Mother Gothel kidnapped her in order to make herself young. But one day, Rapunzel met a thief of the kingdom as they journeyed through the kingdom itself to view the magic lanterns, falling in love in the process.
Anna was an energetic 18-year-old who had a queen as her sister. She fell in love with the neighboring prince Hans. But when her sister cursed the kingdom in eternal winter and ran away, abandoning her own love, so melt her sister's froozen heart.
Haunted by the time her ice magic almost killed her sister, Anna, the 21-year-old princess tried to suppress her powers and prevented anyone from knowing of that magic. However, when the power slipped out and cursed the entire kingdom, Arendelle, she fled the country and locked away her heart.