Czerwień was a West Slavic settlement located near the site of modern Czermno near Tyszowce. In early Middle Ages, the town was the administrative centre of the so-called Czerwień Towns, that is the region roughly correspondent to later Red Ruthenia. The town itself had been destroyed by a Tartar raid around 1289, never to be rebuilt. Its role as the local administrative centre was taken over by the town of Bełz.
In addition to being the name of an ancient city, long since destroyed, Czerwien was the name of a land or province of Poland situated in the southeast of Poland.
Most of the land of Czerwien was seized by the communist Soviet Union, first in September 1939, when the USSR was an axis ally of Nazi Germany and both Germany and the Soviet Union invaded Poland and divided the Polish nation between them.
Then at the end of the Second World War, the Soviet Union relied on a pact agreed with the Allies - USA and the U.K., that Russia could retain their sphere of influence over the eastern territories of Europe including the Baltic States, Poland, Czechoslovakia, Hungary and Romania. In addition to keeping influence, by imposing communism, they annexed entire nations - the Baltic States, or territory from the remainder - eastern Poland, eastern Czechoslovakia, eastern Hungary and northern Romania). Czerwien is one of those annexed territories. The main cities in Czerwien, taken into the USSR and now in Ukraine are the famous city of Lwow, Kolomea, Kowel, Lutsk, Rovno, Sokal, Stryy, Ternopol, etc. Only a very small part of the original Czerwien province remains in present-day Poland.
Czerwien was such an important province to Poland that during World War II, one of the new Polish squadrons in the RAF was named No. 309 "Land of Czerwien" (309 Dywizjon Współpracy "Ziemi Czerwieńskiej"). No. 309 Sqn was a Polish Fighter-Reconnaissance squadron formed in Great Britain at Renfrew in November 1940 as part of an agreement between the Polish government-in-exile and the United Kingdom government. Initially, it was a reconnaissance squadron, but later it became a fighter squadron for bomber escort and ground attack during the latter half of World War II. In June 1942, B flight switched from Lysanders to Mustangs, then in January 1944, the remainder of the squadron became fighters, first Hurricanes, then Mustangs between Sept to Nov. 1944.