King of Ruthenia
The King of Ruthenia (Latin: Rex Rutheniae) or King of the Ruthenians (Latin: Rex Ruthenorum), also known as the King of Rus' or King of Russia (Latin: Rex Rusiae, Rex Russiae; Rex Rusciae; Ukrainian: Король Русі), were royal titles held or claimed by various medieval and later monarchs and dynasts, mainly among various East Slavic, but also Polish, Lithuanian and Hungarian rulers and princes. During the 13th and 14th centuries, principal claimants on those titles were rulers of Galicia–Volhynia.