Very little is known about years when Jaunutis ruled. Those were quite peaceful years, as the Teutonic Knights were led by ineffective Ludolf König. His brothers were much more active: Algirdas attacked Mozhaysk, Livonian Order, defended Pskov, Kęstutis was helping Liubartas in succession disputes in Halych-Volhynia. The Bychowiec Chronicle mentions that Jaunutis was supported by Jewna, presumed wife of Gediminas and mother of his children. She died ca. 1344 and soon after Jaunutis lost his throne. If he was indeed protected by his mother, then it would be an interesting example of influence held by queen mother in pagan Lithuania. However, a concrete stimulus might have been a major reise planned by the Teutonic Knights in 1345. Jaunutis was supported by his brother Narimantas, who traveled to Jani Beg, Khan of the Golden Horde, to form an alliance against Algirdas and Kęstutis. Jaunutis was imprisoned in Vilnius, but managed to escape and went to his brother-in-law Simeon of Russia in Moscow. There Jaunutis was baptized as Iwan or Ioann, but failed to solicit help (possibly because his sister Aigusta, wife of Simeon, died the same year). Both Jaunutis and Narimantas had to reconcile with Algirdas. Jaunutis became the Duke of Zasłaŭje. He is presumed to have died ca. 1366 because he is mentioned for the last time in a treaty with Poland in 1366, and not mentioned in a treaty with Livonia in 1367. He had twos sons, Symeon Zaslawski and Michal Zaslawski. Michal ruled Zasłaŭje until his death on August 12 1399.