Principality of Halych
Busk has a long history. First mentioned in 1097 in Primary Chronicle as Bug City (Ruthenian: бужьсъкъ городъ, buzhesk horod) in the context of the dispute between Rus' princes for border area between Principality of Halych and Volhynian principality. Bug City was named due to its location near Western Bug which locally is known as Bug river.