King of Ruthenia

King of Rus', King of Ruthenia, King of Galicia and Volhynia, Land of Rus' Lord and Heir (Ukrainian:"Король Русі";Latin: "Rex Rusiae", "Rex Galiciae et Lodomeriae", "Terrae Russiae Dominus 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 Kingdom of Galicia–Volhynia. By the 15th century the title was used as a claim by other royal houses.
List of kings of Rus'.
Kings of Rus' (Kingdom of Rus').
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
After 1378.
In the subsequent years, all Kings of Poland styled themselves "Lord of Rus’ (or Ruthenia)". Simultaneously, the tsars of Russia adopted from 1547 onwards the title "Tsar of All-Rus’ ". The Hungarian kings continued to use the title of "King in Halych and Volhynia", later taken over together with the Hungarian Crown by the Holy Roman emperors.
After Partitions of Poland.
After the Partitions of Poland, the tsars of Russia styled themselves "Emperor of all the Russias", while the Holy Roman Emperors (later emperors of Austria and of Austria-Hungary) used the title of "King of Galicia and Lodomeria" drawn from the historical claims of Hungarian Kings to Halych–Volhynia to justify the annexations of territories belonging to Polish-Lithuanian Commonwealth, in spite of the fact that the newly established rump puppet Kingdom of Galicia and Lodomeria was included in the Austrian instead of Hungarian part of the empire, the true historical claimant of the region. Both monarchies were abolished upon the end of World War I.