Question: What is this region highly contested between Poland and Lithuania called in Polish where Lithuanian Education Society Rytas is located? 

Context paragraphs:
Lithuania–Poland relations: Polish–Lithuanian relations date from the 13th century, after the Grand Duchy of Lithuania under Mindaugas acquired some of the territory of Rus' and thus established a border with the then-fragmented Kingdom of Poland.  Polish-Lithuanian relations subsequently improved, ultimately leading to a personal union between the two states.  From the mid-16th to the late-18th century Poland and Lithuania merged to form the Polish–Lithuanian Commonwealth, a state that was dissolved following their partition by Austria, Prussia and Russia.  After the two states regained independence following the First World War, Polish-Lithuanian relations steadily worsened due to rising nationalist sentiments.  Competing claims to the Vilnius region led to armed conflict and deteriorating relations in the interwar period.  During the Second World War Polish and Lithuanian territories were occupied by both the Soviet Union and Nazi Germany, but relations between Poles and Lithuanians remained hostile.  Following the end of World War II, both Poland and Lithuania found themselves in the Eastern Bloc, Poland as a Soviet satellite state, Lithuania as a Soviet republic.  With the fall of communism relations between the two countries were reestablished.

BC Lietuvos rytas: BC Lietuvos rytas, also known as Rytas, is a Lithuanian professional basketball club based in Vilnius, Lithuania.  The club, founded in 1997 on the basis of another club, BC Statyba, is one of the most successful Lithuanian basketball clubs.  Rytas, among other titles, have won two EuroCup titles, five Lithuanian League titles, three Lithuanian Cups and three Baltic Championships.  Lietuvos rytas plays their home games at 11,000-seat Siemens Arena and 2,500-seat Lietuvos rytas Arena.

Lithuanian–Soviet War: The Lithuanian–Soviet War or Lithuanian–Bolshevik War (Lithuanian: "karas su bolševikais" ) was fought between newly independent Lithuania and the Russian Soviet Federated Socialist Republic in the aftermath of World War I.  It was part of the larger Soviet westward offensive of 1918–1919.  The offensive followed retreating German troops with intentions to establish Soviet republics in Ukraine, Belarus, Lithuania, Latvia, Estonia, Poland and link up with the German Revolution.  By the end of December 1918 Soviet forces reached Lithuanian borders.  Largely unopposed, they took one town after another and by the end of January 1919 controlled about ⅔ of the Lithuanian territory.  In February the Soviet advance was stopped by Lithuanian and German volunteers, who prevented the Soviets from capturing Kaunas, the temporary capital of Lithuania.  From April 1919 the Lithuanian war went parallel with the Polish–Soviet War.  Poland had territorial claims over Lithuania, especially the Vilnius Region, and these tensions spilled over into the Polish–Lithuanian War.  Historian Norman Davies summarized the situation: "the German army was supporting the Lithuanian nationalists, the Soviets were supporting the Lithuanian communists and the Polish Army was fighting them all."  In mid-May the Lithuanian army, now commanded by General Silvestras Žukauskas, began an offensive against the Soviets in northeastern Lithuania.  By mid-June the Lithuanians reached the Latvian border and cornered the Soviets among lakes and hills near Zarasai, where the Soviets held out until the end of August 1919.  The Soviets and Lithuanians, separated by the Daugava River, maintained their fronts until the Battle of Daugavpils in January 1920.  As early as September 1919 the Soviets offered to negotiate a peace treaty, but talks began only in May 1920.  The Soviet–Lithuanian Peace Treaty was signed on July 12, 1920.  Soviet Russia fully recognized independent Lithuania.

Jonas Steponavičius: Jonas Steponavičius (10 March 1880 – 8 December 1947) was a Lithuanian Roman Catholic priest active in Lithuanian cultural and political life.  He was ordained a priest in 1906 and earned Ph.D. in psychology in 1912.  He returned to Lithuania and became a priest in the Church of St. Johns, Vilnius.  He joined Lithuanian cultural life, becoming the first chairman of the Lithuanian Education Society Rytas which established and maintained Lithuanian-language one-room schools. His attempt at holding Lithuanian-language service at the Church of St. Johns caused Polish protests and he was reassigned to the Dominican Church of the Holy Spirit and later to Semeliškės.  During World War I, he served as a military chaplain in the Caucasus Campaign.  After returning to Lithuania, he joined the Lithuanian Christian Democratic Party and was elected four times to the Seimas (parliament) from 1920 to the December 1926 coup d'état that brought the regime of Antanas Smetona.  He retired from politics and became a school director in Zarasai and a teacher in Utena.  In mid-1944, Steponavičius was one of the organizers of the Fatherland Defense Force, a short-lived military unit formed to combat approaching Soviet forces.  He retreated to Germany where he died in 1947.

1938 Polish ultimatum to Lithuania: The 1938 Polish ultimatum to Lithuania was an ultimatum delivered to Lithuania by Poland on March 17, 1938.  The Lithuanian government had steadfastly refused to have any diplomatic relations with Poland after 1920, protesting the annexation of the Vilnius Region by Poland.  As pre-World War II tensions in Europe intensified, Poland perceived the need to secure its northern borders.  Five days earlier, Poland, feeling supported by international recognition of the annexation of Austria by Nazi Germany, decided to deliver an ultimatum to Lithuania.  The ultimatum demanded that the Lithuanian government unconditionally agree to establish diplomatic relations with Warsaw within 48 hours, and that the terms be finalized before March 31.  The establishment of diplomatic relations would mean a "de facto" renunciation of Lithuanian claims to the region containing its historic capital, Vilnius (known in Polish as Wilno).

Union of Horodło: The Union of Horodło or Pact of Horodło was a set of three acts signed in the town of Horodło on 2 October 1413.  The first act was signed by Władysław II Jagiełło, King of Poland, and Vytautas, Grand Duke of Lithuania.  The second and third acts were composed by the Polish nobility (szlachta) and Lithuanian boyars respectively.  The union amended the earlier Polish–Lithuanian unions of Krewo and Vilnius–Radom.  Politically, Lithuania received more autonomy as, after the death of Vytautas, the Lithuanian nobles could choose another Grand Duke instead of passing the title to Władysław II Jagiełło or his heir.  However, culturally, Lithuania and Poland grew closer.  Lithuania adopted Polish institutions of castellans and voivodes. Catholic Lithuanian nobles and church officials were granted equal rights with the Polish nobles and clergy.  Forty-seven selected Lithuanian nobles were adopted by Polish families and granted Polish coats of arm.  Thus the union signified the beginnings of Polonization of Lithuanian culture and the rise of the Lithuanian nobility.  It was one of the major steps towards the modernization and Europeanization of Lithuania.

Lithuania Minor: Lithuania Minor (Lithuanian: "Mažoji Lietuva" ; German: "Kleinlitauen" ; Polish: "Litwa Mniejsza" ; Russian: Máлая Литвá ) or Prussian Lithuania (Lithuanian: "Prūsų Lietuva" ; German: "Preußisch-Litauen" , Polish: "Litwa Pruska" ) is a historical ethnographic region of Prussia, later East Prussia in Germany, where Prussian Lithuanians or Lietuvininkai lived.  Lithuania Minor enclosed the northern part of this province and got its name due to the territory's substantial Lithuanian-speaking population.  Prior to the invasion of the Teutonic Knights in the 13th century, the main part of the territory later known as Lithuania Minor was inhabited by the tribes of Skalvians and Nadruvians.  The land became depopulated to some extent during the warfare between Lithuania and the Order.  The war ended with the Treaty of Melno and the land was resettled by Lithuanian newcomers, returning refugees, and the remaining indigenous Baltic peoples; the term Lithuania Minor appeared for the first time between 1517 and 1526.  With the exception of the Klaipėda Region, which became a mandated territory of the League of Nations in 1920 by the Treaty of Versailles and was annexed to Lithuania from 1923 to 1939, the area was part of Prussia until 1945.  Today a small portion of Lithuania Minor is within the borders of modern Lithuania and Poland while most of the territory is part of the Kaliningrad Oblast of Russia.

Valia College: Valia College is an education institute, established in 1961, run by Cosmopolitan Education Society located at D.N. Nagar, in Andheri West, Mumbai.  The college is affiliataed with University of Mumbai and accredited by NAAC.  In 1961, it was the spirit of idealism that inspired a group of like minded residents of D. N. Nagar, Andheri (W) to establish a quality educational institution.  Thus, was the Cosmopolitan Education Society was born.  Under its Aegis, the society runs the Valia College of Commerce and Arts which offers various programmes at undergraduate and post-graduate levels.

Republic of Central Lithuania: The Republic of Central Lithuania or Middle Lithuania (Polish: "Republika Litwy Środkowej" , Lithuanian: "Vidurio Lietuvos Respublika" , Belarusian: Рэспубліка Сярэдняе Літвы / "Respublika Siaredniaje Litvy" ), or Central Lithuania (Polish: "Litwa Środkowa" , Lithuanian: "Vidurio Lietuva" or "Vidurinė Lietuva" , Belarusian: Сярэдняя Літва / "Siaredniaja Litva" ), was a short-lived political entity, which did not gain international recognition.  The republic was created in 1920 following the staged rebellion of soldiers of the 1st Lithuanian–Belarusian Infantry Division of the Polish Army under Lucjan Żeligowski, supported by the Polish air force, cavalry and artillery.  Centered on the historical capital of the Grand Duchy of Lithuania, Vilna (Lithuanian: "Vilnius" , Polish: "Wilno" ), for eighteen months the entity served as a buffer state between Poland, upon which it depended, and Lithuania, which claimed the area.  After a variety of delays, a disputed election took place on January 8, 1922, and the territory was annexed to Poland.

Lithuanian Education Society Rytas: The Lithuanian Education Society Rytas (Lithuanian: "Lietuvių švietimo draugija „Rytas“" ; "rytas" means "morning" or "dawn") was a Roman Catholic society fostering education in the Lithuanian language mostly in the Vilnius Region, then fiercely contested between Lithuania and the Second Polish Republic, now split between Lithuanian and Belarus.  Established in 1913, the society maintained some 100 primary schools (mostly one-room schools), 50 evening classes, and Teacher's Seminary in Vilnius (Wilno, Vilna) in 1927.  Due to political tensions between Poland and Lithuania as well as wider Polonization policies, Rytas faced increasing difficulties and restrictions in maintaining its schools.  Similar situation existed with Polish schools in Lithuania (see Lithuanization).  The situation continued to worsen as both sides increased restrictions in retribution.  As schools were closed, Rytas shifted its focus to maintaining community reading rooms.  After the death of Józef Piłsudski in 1935, the rooms were often raided by police and closed.  Eventually, the society was abolished by Polish authorities in February 1938.  Only the Vytautas the Great Gymnasium was allowed to operate.  After the Polish ultimatum of March 1938, diplomatic relations were established between Poland and Lithuania and Rytas was allowed to operate again in May 1939.  It could not resume its activities due to World War II and was abolished again soon after the occupation of Lithuania by the Soviet Union in June 1940.  The society, with the same mission of promoting Lithuanian-language education, was reestablished in 2004.

Supporting paragraphs: Lithuanian Education Society Rytas 1938 Polish ultimatum to Lithuania
Answer: Wilno