In the early 1320s,[3] Gediminas won the Battle on the Irpen' River against Stanislav of Kiev and captured the city.[4] The Tatars, who also claimed Kiev, retaliated during the years 1324–1325. The Lithuanian Chronicles mention that Gediminas installed his deputy Algimantas, son of Mindaugas from Olshanski family. There were some attempts to claim that Algimantas was Fiodor's pagan name, but they are discharged by evidence that Algimantas was baptized as Mikhail.[5]
For a long time scholars assumed that Fiodor was of Rurikid origin (descendant of Oleg I of Chernigov) because of his Christian name. However, in 1916, Russian historian Mikhail Priselkov published a list of property belonging to Theognostus, the metropolitan of Moscow.[10] The list, compiled in 1331, listed two silver cups given to Theognostus by Fiodor, brother of Gediminas.[7] Modern historians agree that Fiodor from the list and Fiodor from Kiev was one and the same person. No other evidence survives regarding Fiodor's family.
^Historians disagree on exact dating: Maciej Stryjkowski provided 1320/21, Aleksandr I. Rogov argues for 1322, C. S. Rowell for 1323, Feliks Shabul'do for 1324, Romas Batūra for 1325.
^Rowell, C. S. (1994). Lithuania Ascending: A Pagan Empire Within East-Central Europe, 1295-1345. Cambridge Studies in Medieval Life and Thought: Fourth Series. Cambridge University Press. p. 97. ISBN978-0-521-45011-9.
^Simas Sužiedėlis, ed. (1970–1978). "Theodore". Encyclopedia Lituanica. Vol. V. Boston, Massachusetts: Juozas Kapočius. pp. 446–447. LCCN74-114275.
^Gudavičius, Edvardas (2004). "Teodoras". In Vytautas Spečiūnas (ed.). Lietuvos valdovai (XIII-XVIII a.): enciklopedinis žinynas (in Lithuanian). Vilnius: Mokslo ir enciklopedijų leidybos institutas. p. 31. ISBN5-420-01535-8.
^(in Lithuanian) "Teodoras". Lietuvių enciklopedija. Vol. 31. Boston, Massachusetts: Lietuvių enciklopedijos leidykla. 1953–1966. p. 49. LCCN55020366.
