Red Ruthenia or Red Russia ( or , ,) is a historic term used since medieval times to refer to the area known today as south-eastern Poland and Western Ukraine; first mentioned in Polish historic chronicles in the 1321, was the part of Rus' incorporated to Poland by Casimir the Great in the 14th century.
Ethnographers explain that the term was applied from the old-Slavonic use of colours for the cardinal points on the compass. The ancient totem-god Svetovid had four faces. The northern face of this totem was white, the western face red, the southern black, and the eastern green. However, some inconsistency exists in the theory such as the fact that nothing is known about Green Ruthenia and the Black Ruthenia is located to the west from the White Ruthenia. Another theory suggests that the name could have arisen from already established polity of the Red Cities (Grody Czerwieńskie). Some towns in the area carry names related to the color red.
Since the 14th century and after the disintegration of Ruthenia the area of Red Ruthenia was contested by numerous historical states such as the Grand Duchy of Lithuania (Gediminids), Kingdom of Poland (Piasts), Kingdom of Hungary, Kingdom of Ruthenia, and others. After the Galicia–Volhynia Wars most of the Red Ruthenia for some 400 years became part of Poland, incorporated as the Ruthenian Voivodeship. The historic Red Ruthenia, reaching on its south-west to Przemyśl and Sanok, has been inhabited for nearly the last ten centuries mostly by the Ruthenian population.
The traditional population of Red Ruthenia was perhaps Lendians, and on the borders Boykos, Lemkos and a German group of so-called Głuchoniemcy (Walddeutsche) which became Polish. There were also several Jews and Armenians here, as well as Poles.
Marcin Bielski claimed that Bolesław I Chrobry had settled some Germans in the region to defend the borders against Hungary and Kievan Rus', however, they turned to farming. Maciej Stryjkowski mentioned Germans peasants near Rzeszów, Przemyśl, Sanok, and Jarosław, describing them as good farmers. De facto, it was Casimir the Great who settled German burghers and peasants on the border of Lesser Poland and Red Ruthenia to join the acquired territory with the rest of kingdom. While evaluating the size of the population of late medieval Poland, one should take into account the development of internal colonisation and the migration of Polish people to Red Ruthenia, Zips, and Podlachia, whom Ukrainians called the "Mazury", poor peasant migrants, chiefly from Mazowsze.
It was in the second half of the 14th century that a new wave of settlers i.e. the Vlachs, came from the south-eastern Carpathians and quickly spread over southern Red Ruthenia. From the 15th century, however, the Ruthenian element began to prevail there. Nevertheless, it was not until the 16th century that the Vallachian population in the Bieszczady Mountains and the Lower Beskid was completely Ruthenized.
Between the 14th and 16th centuries the area in question underwent a rapid urbanization process, resulting in the founding of over 200 new towns built in the so-called German model (iure Theuthonico), which had been virtually unknown in Red Ruthenia when it was an independent state (Duchy of Halych, before 1340).
In the Middle Ages, it was part of Ruthenian Kingdom of Galicia–Volhynia. It came under Polish control in 1340, when Casimir III of Poland acquired it Since these times the name Ruś Czerwona is recorded, translated as "Red Ruthenia", applied to a territory extended up to the Dniester River, with priority gradually transferred to Przemyśl (Peremyshl). Since the times of Władysław Jagiełło, the Przemyśl Voivodeship was called the Ruthenian Voivodeship ("województwo ruskie"), with the priority eventually transferred to Lwów (Lviv). It consisted of five lands: Lwów, Sanok, Halicz (Halych), Przemyśl (Peremyshl), and Chełm (Kholm). The city of Halych gave the name to Galicia.
In October 1372 Władysław Opolczyk was unexpectedly deprived of the office of Count palatine. Although he retained most of his castles and goods in Hungary, his political influence was significantly decreased. As a compensation, he was made Governor of the Hungarian Galicia. In this new position, the Duke of Opole successfully contributed to the economic development of the territories entrusted to him. Władysław mainly resided in Lwów, but at the end of his rule he spent more time in Halicz. The only serious conflict during his time as Governor was related to his approach to the Russian Orthodox Church, which caused the anger of the local boyars, who were strongly Catholics. Probably following Władysław's advices, in 1374 King Louis I published an earthly privilege for the nobility in Koszyce, which ensured the succession of the King's daughters after his death.
Under Polish rule, 325 towns were founded between the 14th and the second half of the 17th century, most in the 15th and 16th centuries (96 and 153 respectively).
Between World War I and World War II this land belonged to the Second Polish Republic. Presently, this area is split. The Western part is the area of South-Eastern Poland (around Rzeaszów, Przemyśl, Zamość and Chełm); the Eastern part (around Lviv) is a part of Western Ukraine.