Andrei of Polotsk (Belarusian: Андрэй Альгердавіч , Lithuanian: "Andrius Algirdaitis" Polish: "Andrzej Olgierdowic" , ca. 1325 – 12 August 1399, in the Battle of the Vorskla River) was the eldest son of Algirdas, Grand Duke of Lithuania, and his first wife Maria of Vitebsk.
 He was Duke of Pskov (through his deputy Yuri, 1342–1348) and Polotsk (1342–1387).
 As the eldest son of the Grand Duke, Andrei claimed his right to the throne after his father's death in 1377.
 Algirdas left Jogaila, his eldest son with his second wife Uliana of Tver, as the rightful heir.
 Andrei's rivalry with Jogaila, Grand Duke of Lithuania and later King of Poland, eventually led to his demise.
The Gediminas Bridge (Lithuanian: "Gedimino tiltas" ) is a bridge in Kupiškis, Lithuania.
 The bridge crosses the Kupa River.
 It is one of eight bridges in Kupiškis.
 The bridge is named after the street that crosses the bridge.
 Gediminas (c. 1275–1341) was Grand Duke of Lithuania from 1315 or 1316 until his death.
The Lithuanian Civil War of 1381–1384 was the first struggle for power between the cousins Jogaila, Grand Duke of Lithuania and later King of Poland, and Vytautas the Great.
 It began after Jogaila signed the Treaty of Dovydiškės with the Teutonic Knights which was aimed against his uncle Kęstutis, father of Vytautas.
 Kęstutis briefly seized power in the Grand Duchy, but was betrayed by adherents of Jogaila primarily from Vilnius.
 During negotiations for a truce Kęstutis and Vytautas were arrested and transported to the Kreva Castle.
 Kęstutis died there a week later but Vytautas managed to escape and then sought an alliance with the Teutonic Knights.
 Subsequently their joint forces raided Lithuanian lands.
 Eventually the cousins were reconciled as Jogaila needed internal stability in anticipation of negotiations with the Grand Duchy of Moscow and the Kingdom of Poland regarding the possible Christianization of Lithuania.
 The war did not settle the power struggle; it continued during the next Lithuanian Civil War (1389–1392) which was resolved by the signing of the Ostrów Agreement.
 After more than ten years of struggle, Vytautas finally became the Grand Duke of Lithuania and ruled the country for thirty-eight years.
Gediminas (  1275 – December 1341) was Grand Duke of Lithuania from 1315 or 1316 until his death.
 He is credited with founding this political entity and expanding its territory which, at the time of his death, spanned the area ranging from the Baltic Sea to the Black Sea.
 Also seen as one of the most significant individuals in early Lithuanian history, he was responsible for both building Vilnius, the capital of Lithuania, and establishing a dynasty that can be traced to other European monarchies such as Poland, Hungary and Bohemia.
Vainius or Voin (died between 1338 and 1342) was the Prince of Polotsk from 1315 to his death.
 Very little is known about Vainius, brother of Gediminas, Grand Duke of Lithuania.
 He is mentioned in written sources in 1324 for the first time.
 In 1326 he, already as Prince of Polotsk, signed a treaty with the Livonian Order and Novgorod.
 His only known son Liubko died in 1342 during fights with the Livonian Order.
Michael Žygimantaitis (Lithuanian: "Mykolas Žygimantaitis" , Polish: "Michał Bolesław Zygmuntowicz" ; before 1406 – shortly before February 10, 1452 in Moscow) was the last male descendant of Kęstutis, Grand Duke of Lithuania.
 He supported his father Sigismund Kęstutaitis in power struggles with Švitrigaila.
 In 1435 he led his father's army to victory in the Battle of Pabaiskas.
 After his father's assassination in 1440, Michael unsuccessfully fought against Casimir IV Jagiellon for the title of the Grand Duke of Lithuania.
 At first Michael was supported by Samogitia, but in 1441 Casimir issued a privilege confirming Samogitia's semi-autonomous status and thus avoiding a civil war.
 Until 1447 he was supported by Dukes of Masovia.
 In 1448 Michael asked help from the Crimean Khanate.
 With their help he attacked and shortly took control of Kiev, Starodub, Novhorod-Siversky.
 Soon he was captured and transported to the Grand Duchy of Moscow where he died under unclear circumstances (possibly poisoned).
 He was buried in Vilnius Cathedral.
Manvydas or Monwid (Russian: Монтивид ; died in 1348?)
 was the eldest son of Gediminas, Grand Duke of Lithuania, and inherited Kernavė and Slonim after his father's death in 1341.
 Nothing else is known about his life.
 Matthias of Neuenburg mentioned that two sons of Gediminas perished in the Battle of Strėva in February 1348.
 One was Narimantas and the other is believed to be Manvydas.
The Lithuanian Civil War of 1389–92 was the second civil conflict between Jogaila, King of Poland and Grand Duke of Lithuania, and his cousin Vytautas.
 At issue was control of the Grand Duchy of Lithuania, then the largest state in Europe.
 Jogaila had been crowned King of Poland in 1386; he installed his brother Skirgaila as ruler of Lithuania.
 Skirgaila proved unpopular and Vytautas attempted to depose him.
 When his first attempt to take the capital city of Vilnius failed, Vytautas forged an alliance with the Teutonic Knights, their common enemy – just as both cousins had done during the Lithuanian Civil War between 1381 and 1384.
 Vytautas and the Knights unsuccessfully besieged Vilnius in 1390.
 Over the next two years it became clear that neither side could achieve a quick victory, and Jogaila proposed a compromise: Vytautas would become Grand Duke and Jogaila would remain Superior Duke.
 This proposal was formalized in the Ostrów Agreement of 1392, and Vytautas turned against the Knights.
 He went on to reign as Grand Duke of Lithuania for 38 years, and the cousins remained at peace.
Karijotas or Koriat (baptized "Michal"; died between 1358 and 1363) was the Duke of Navahrudak (Lithuanian: "Naugardukas" ) and Vaŭkavysk (Lithuanian: "Valkaviskas" ), one of the sons of Gediminas, Grand Duke of Lithuania.
The family of Gediminas is a group of family members of Gediminas, Grand Duke of Lithuania (ca. 1275–1341), who interacted in the 14th century.
 The family included the siblings, children, and grandchildren of the Grand Duke and played the pivotal role in the history of Lithuania for the period as the Lithuanian nobility had not yet acquired its influence.
 Gediminas was also the forefather of the Gediminid dynasty, which ruled the Grand Duchy of Lithuania from 1310s or 1280s to 1572.

Question: What was the name of the father of the Grand Duke of Lithuania who reigned between 1315-1341?  
Answer: Karijotas