 More than 2500 folk and fairy tales have been cataloged under this taxonomy; the AaTh or Aarne–Thompson number is as well-known to folklorists as Francis James Child's identification of ballads are to scholars of folk songs.Vladimir Propp was a Russian formalist scholar.He criticized Aarne's work for ignoring what motifs "did" in a tale, and analysed the basic plot, or action, components of Russian folk tales to identify their simplest irreducible narrative elements.