Andrei of Polotsk
Andrei of Polotsk (, , , 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 the Prince 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. Prince of Pskov and Polotsk In 1342, Andrei joined his father Algirdas and uncle Kęstutis in a war against the Livonian Order to help the Pskov Republic. The Republic asked him to stay as a prince of Pskov so that his presence would guarantee continuous support from Algirdas. Andrei accepted and was baptized in Orthodox rite (his pagan name is unknown). However, he stayed there for a very short time and returned to Lithuania. Reasons are not entirely clear, but historians speculate it was related to death of his great-uncle Vainius, Duke of Polotsk. Polotsk was vital to Lithuanian interests as it was situated between Lithuania and the Livonian Order. Andrei became the Prince of Polotsk and helped defend Lithuania against Livonian attacks. In Pskov, Andrei left his deputy, otherwise unknown Yuri. Lithuanian historian Alvydas Nikžentaitis speculated that this Yuri could have been a grandson of Gediminas. Yuri remained in Pskov until 1348 when Teutonic Knights organized a large attack against Lithuania (see Battle of Strėva). Pskov's army was helping Novgorod against Sweden when Livonian Order attacked a Pskovian fortress at Izborsk. Yuri died in the attack. Because Lithuanians were unable to defend Pskov, the city refused to accept another deputy from the Grand Duchy of Lithuania. Andrei responded with repressions: all merchants from Pskov were arrested and their goods confiscated. The friendly relationship between Pskov and Lithuania was terminated. Andrei remained as Prince of Polotsk for the next three decades. Struggle against Jogaila After the death of Algirdas in 1377, Andrei, as the eldest son, rivaled his half-brother Jogaila, whom Algirdas had designated as his heir. Jogaila at the time enjoyed strong support from his uncle Kęstutis. Andrei organized an anti-Lithuanian coalition with Polotsk, Grand Duchy of Moscow, and the Livonian Order. In 1379, Moscow's army attacked eastern territories of the Grand Duchy; Moscow and Lithuania were at peace since the Treaty of Lyubutsk in 1372. Andrei's brother Dymitr I Starszy did not defend the Principality of Trubetsk and Starodub. However, the Russian army did not remain in taken territories and retreated back to Moscow; Andrei and Dymitr followed it. Jogaila signed a ten-year truce with the Teutonic Knights on September 29, 1379 and a truce with the Livonian Order on February 27, 1380, thus fracturing the coalition. He further enlisted Mamai, a powerful warlord of the Golden Horde, and Oleg II of