Kingdom of Rus in the context of "Principality of Belz"

Duchy of Belz or Principality of Belz was a duchy, formed in the late 12th century in Kievan Rus. During its history the duchy was a constituent part of some other political entities such as the Kingdom of Rus, the Kingdom of Hungary, Duchy of Masovia when eventually in the late 14th century was incorporated into Poland becoming later the Bełz Voivodeship.