 In 1966, Jan Harold Brunvand argued that the main source for the play was not literary, but the oral folktale tradition.He argued the Petruchio/Katherina story represents an example of Type 901 ('Shrew-taming Complex') in the Aarne–Thompson classification system.Brunvand discovered 383 oral examples of Type 901 spread over thirty European countries, but he could find only 35 literary examples, leading him to conclude "Shakespeare's taming plot, which has not been traced successfully in its entirety to any known printed version, must have come ultimately from oral tradition."