Vladimir Propp studied hundreds of Russian folktales and identified common narrative structures and character types that appear across stories. He observed that narratives are shaped by specific character functions and actions, and identified 31 possible stages or "functions" that stories may include in a fixed sequence, such as a hero, villain, dispatcher, donor, and helper. Todorov also analyzed narrative structure and proposed stories begin with an equilibrium, experience a disruption, and conclude with the restoration of a new equilibrium.