Danutė of Lithuania was a Lithuanian princess, daughter of Kęstutis

Kestutis

Kęstutis was monarch of medieval Lithuania. He was the Duke of Trakai and governed the Grand Duchy of Lithuania, 1342–82, together with his brother Algirdas , and with his nephew Jogaila...

, Grand Duke of Lithuania. She was married to Janusz I of Warsaw, one of the dukes of Masovia

Dukes of Masovia

The Dukes of Masovia were a line of the Piast dynasty who ruled in Masovia. The following is a list of all rulers of the Duchy of Masovia and its parts...

. Very little reliable information is known about her life.

The date of her marriage is confused in many sources. Jan Długosz in one instance claims that she got married in 1388 together with her cousin Alexandra of Lithuania

Alexandra of Lithuania

Alexandra was the youngest daughter of Grand Duke of Lithuania Algirdas and his second wife Uliana of Tver. In 1387 Alexandra married Siemowit IV, Duke of Masovia...

, daughter of Algirdas

Algirdas

Algirdas was a monarch of medieval Lithuania. Algirdas ruled the Grand Duchy of Lithuania from 1345 to 1377, which chiefly meant monarch of Lithuanians and Ruthenians...

. In another instance the historian claims that she was already married in 1382. Analysis of contemporary sources suggests that the marriage took place between 1371 and 1379. In 1379 Kęstutis in negotiations with the Teutonic Knights

Teutonic Knights

The Order of Brothers of the German House of Saint Mary in Jerusalem , commonly the Teutonic Order , is a German medieval military order, in modern times a purely religious Catholic order...

 called Günter von Hohenstein, komtur

Komtur

Komtur was a rank within military orders, especially the Teutonic Knights. In the State of the Teutonic Order, the Komtur was the commander of a basic administrative division called Kommende . A Komtur was responsible for the alimentation of the Knights by the yield from the local estates, he...

 of Ostróda

Ostróda

Ostróda is a town in Ostróda County in the Warmian-Masurian Voivodeship in Poland, with 33,603 inhabitants as of January 1, 2005. It lies in the Masurian Lake District and is a growing tourist site owing to its relaxing natural surroundings.-History:...

, godfather of Danutė. It means that by that time she was already baptized and married. In 1371 Pope Gregory XI

Pope Gregory XI

Gregory XI was pope from 1370 until his death.-Biography:He was born Pierre Roger de Beaufort, in Maumont, in the modern commune of Rosiers-d'Égletons, Limousin around 1336. He succeeded Pope Urban V in 1370, and was pope until 1378...

 sent a letter to Siemowit III of Masovia

Siemowit III of Masovia

Siemowit III of Masovia was a prince of Masovia and a co-regent of the lands of Warsaw, Czersk, Rawa, Gostynin and other parts of Masovia.- Life :...

, father of Janusz, urging him not to allow his subordinates to help pagan Lithuanians

Lithuanian mythology

Lithuanian mythology is an example of Baltic mythology, developed by Lithuanians throughout the centuries.-History of scholarship:Surviving information about Baltic paganism in general is very sketchy and incomplete. As with most ancient Indo-European cultures Lithuanian mythology is an example of...

. If the marriage took place by that time, the pope would have certainly condemned the Christian duke for the alliance with the pagans.

In 1382, after escaping from Kreva

Kreva

Kreva is a township in Hrodna Voblast, Belarus.-History:The Kreva Castle, constructed of brick, was built by the Grand Duke Gediminas of Lithuania at the borderland of Lithuanian ethnic lands. After his death in 1341, Kreva became the patrimony of his son and successor, Algirdas...

, Vytautas the Great

Vytautas the Great

Vytautas ; styled "the Great" from the 15th century onwards; c. 1350 October 27, 1430) was one of the most famous rulers of medieval Lithuania. Vytautas was the ruler of the Grand Duchy of Lithuania which chiefly encompassed the Lithuanians and Ruthenians...

 first asked his sister Danutė and his brother-in-law Janusz for help in the Lithuanian Civil War

Lithuanian Civil War (1381–1384)

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,...

 against his cousin Jogaila

Jogaila

Jogaila, later 'He is known under a number of names: ; ; . See also: Jogaila : names and titles. was Grand Duke of Lithuania , king consort of Kingdom of Poland , and sole King of Poland . He ruled in Lithuania from 1377, at first with his uncle Kęstutis...

. However, he did not receive any assistance and had to turn to the Teutonic Knights

Teutonic Knights

The Order of Brothers of the German House of Saint Mary in Jerusalem , commonly the Teutonic Order , is a German medieval military order, in modern times a purely religious Catholic order...

. In 1440, after assassination of his father Sigismund Kęstutaitis

Sigismund Kestutaitis

Sigismund Kęstutaitis was the Grand Duke of Lithuania from 1432 to 1440. Sigismund was his baptismal name; Sigismund's pagan Lithuanian birth name is unknown. He was son of the Grand Duke of Lithuania Kęstutis and his wife Birutė....

, Michał Bolesław Zygmuntowicz might have also sought refuge in Danutė's lands. At the time Danutė was a widow, as Janusz died in 1429. It is believed that she died on May 25, 1448 leaving no heirs.