| Royal Title: | King |
| Realm: | Ruthenia |
| Coatofarms: | Alex_K_Halych-Volhynia.svg |
| Coatofarmssize: | 170 |
| Coatofarmscaption: | Coat of arms of the Kingdom of Galicia–Volhynia |
| First Monarch: | Daniel of Galicia |
| Last Monarch: | Casimir III the Great |
| Residence: | Kholm (1253-1271) Lviv (1271-1349) |
| Appointer: | Hereditary |
| Began: | 1253 |
| Ended: | 1370 |
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) was a title of princes of Galicia and Volhynia, granted by the Pope.
The title was initially issued to the ruling Izyaslavichi of Volhynia. Later the title was passed on to the Romanovichi as rulers of the united Kingdom of Galicia–Volhynia. By the 15th century the title was used as a claim by other royal houses.
See also: Names of Rusʹ, Russia and Ruthenia. In the 13th–14th centuries, many of southwestern Rus' principalities were united under the power of the Kingdom of Rus' (Latin: Regnum Rusiae), historiographically better known as the Kingdom of Galicia–Volhynia. Roman the Great was variously named dux Rutenorum, princeps Ruthenorum or rex Ruthenorum by Polish chroniclers. Danylo of Galicia was crowned Rex Ruthenorum or "king of the Rus'" in 1253.[1] Alternatively, Danylo and his brother Vasylko Romanovych were styled Princeps Galiciae, Rex Russiae, and Rex Lodomeriae in Papal documents, while the population of Halych and Volhynia was called Rusciae christiani and populus Russiae amongst other names. The Gesta Hungarorum (1280) stated that the Carpathian mountains between Hungary and Halych were situated in finibus Ruthenie ("on the borders of Ruthenia").
Galicia–Volhynia declined by mid-14th century due to the Galicia–Volhynia Wars after the poisoning of king Yuri II Boleslav by local Ruthenian nobles in 1340. 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 (...)").[2]
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.[3]
At the death of Casimir III the Great all of titulage was passed over to Louis I of Hungary
In the subsequent years, all Kings of Poland-Lithuania 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 claim the title of King in Halych and Volhynia, later taken over together with the Hungarian Crown by the Holy Roman emperors.
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. 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. All these monarchies were abolished upon the end of World War I. 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. Nevertheless, its throne remained vacant until the ultimate abolition of Hungarian monarchy in 1946.