Emperor Go-Daigo
Go-Daigo did not reward Ashikaga Takauji with a high rank, only the rank of counsellor.  He did not reward many of his other supporters either.  In 1335, Takauji declared himself shogun and rebelled.  Takauji and his army captured Kyoto and set up one of Go-Daigo's relatives as an emperor there.  Go-Daigo ran away from Kyoto and set up a court Yoshino, south of Nara.  Go-Daigo's court only ruled the land nearby.  So for many years, there were two men who said they were emperor of Japan.