King of Rus'

King of Ruthenia', King of Galicia and Volhynia, King of Poland and Ruthenia, Land of Ruthenia Lord and Heir (Latin: Rex Rusiae, Rex Galiciae et Lodomeriae, Rex Polonie et Russie, Terre Russie Domin et Heres) was a title of princes of Galicia and Volhynia, granted by the Pope.

The title was initially issued to the ruling Izyaslavichi branch of Rurik dynasty of Volhynia. Later the title was passed on to Romanovichi as rulers of united Duchy of Galicia and Volhynia. By the 15th century the title was used as a claim by other royal houses.

After the death of Boleslav-Yuri II of Halych, Galicia–Volhynia Wars ensued which resulted in Galicia gradually being annexed by the Kingdom of Poland, between 1349 and 1366, during the reign of Casimir III of Poland.

At the death of Casimir III the Great all of titulage was passed over to Louis I of Hungary

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