King of Ruthenia, King of Rus', King of Galicia and Lodomeria, Lord and Heir of Ruthenian Lands (Latin: Rex Rusiae, Rex Ruthenorum, Rex Galiciae et Lodomeriae, Terrae Russiae Dominus et Heres; Ukrainian: Король Русі, король Галичини і Володимирії, князь і володар Всієї Землі Руської, romanized: Korol Rusi, korol Halychyny i Volodymyrii, kniaz i volodar Vsiiei Zemli Ruskoi) was a title of princes of Galicia and Volhynia, granted by the Pope.

Iohannes Victiensis Liber (page 218) records the death of Boleslav as Hoc anno rex Ruthenorum moritur (...) ("In that year the king of the Ruthenians died (...)").

[5] At the death of Casimir III the Great all of titulage was passed over to Louis I of Hungary Grand Duke of Lithuania Gediminas called himself King of the Lithuanians and [many] Ruthenians in the 1320s.

[citation needed] Part of Galicia was included in the puppet Kingdom of Poland (1916-1918) re-established by the Central Powers and ruled by the Regency Council.

However, the Kingdom of Hungary was formally re-established in 1920 along with its royal titles and styles, and its territory even included at a time the Carpathian Ruthenia, following the breakup of the Second Czechoslovak Republic.