Title: Trojden I, Duke of Masovia
Content:  Trojden I (1284/86 &ndash; 13 March 1341), was a Polish prince, member of the House of Piast, Duke of Czersk after 1310, ruler over Warsaw and Liw after 1313, regent of Płock during 1336–1340. He was the second son of Bolesław II of Płock and his first wife Gaudemantė (Sophia), the daughter of Grand Duke Traidenis of Lithuania. He was named after his maternal grandfather.
Title: Trojden I, Duke of Masovia
Content:  In 1310, when his father was still alive Trojden I received the district of region Czersk. When his father died in 1313, he further received the districts of Warsaw and Liw in addition to his duchy, which made him ruler over all the eastern Masovia. This division didn't satisfy anybody and lead to a brief war between the three brothers in 1316. Apart from a brief mention in the Roczniku miechowskim, the exact details of this conflict are unknown. Initially Trojden I maintained excellent relations with Władysław I Łokietek. Thanks to his intervention, in ca. 1309/10 Trojden I could married Maria, daughter of Yuri I, King of Halych-Volhynia. Thanks to this union, when in 1323 became extinct the 
Title: Trojden I, Duke of Masovia
Content:  of the youngest Masovian Duke, Wenceslaus with the Teutonic Order. This event caused that on 2 January 1326 at Brodnica, Trojden I and his brothers concluded an agreement with the Teutonic Order, which led to a short conflict with Poland and its ally Lithuania. In the following years, Trojden I together with his brothers tried to maneuver between the Polish Kingdom and the Teutonic Order. For instance, in 1329 the Dukes of Masovia supported militarily Władysław I the Elbow-high, while in 1334 they already appeared as allies of the Grand Master. In 1339 Trojden I was again close to the Kingdom of Poland, ruled at the time by Casimir III the Great. Evidence of this was his testimony 
Title: Trojden I, Duke of Masovia
Content:  the Polish-Teutonic trial for the seizure of land from the Piast dynasty. For unknown reasons, Trojden I didn't personally attend the trial, but sent his Chancellor Gunther as his representative. In 1340, his eldest son Bolesław (Yuri II) was poisoned by his own subjects. Trojden I waives his right to succeed his son in Halych-Volhynia in exchange for a large sum of money paid to him by Casimir III. Trojden I died on 13 March 1341 and is buried in the Dominican monastery in Warka, now destroyed. In 1859 his remains were moved to the Church of Our Lady of Carmel in Warka, thanks to the initiative of Piotr Wysocki, as manifestation of the growing Polish nationalism.
Title: Trojden I, Duke of Masovia
Content: 1) Bolesław (Yuri II) (1310 – 21 March 1340), became King of Halych-Volhynia. ; 2) Euphemia (1312 – ca. 11 January 1374), married Casimir I, Duke of Cieszyn. ; 3) Siemowit III (1316/25 – 16 June 1381). ; 4) Casimir I (1329/31 – 26 November/5 December 1355). Around 1309/10, Trojden I married with Maria (bef. 1293 - 11 January 1341), daughter of Yuri I, King of Halych-Volhynia. They had four children:
Title: Trojden II of Płock
Content:  Trojden II of Płock (1403/06 - 25 July 1427 ), was a Polish prince member of the House of Piast from the Masovian branch. He was a Duke of Płock, Rawa Mazowiecka, Gostynin, Sochaczew and Belz during 1426-1427 jointly with his brothers. He was the fourth son of Siemowit IV, Duke of Masovia and Alexandra of Lithuania, daughter of Algirdas.
Title: Trojden I, Duke of Masovia
Content:  Rurikid dynasty in Halych-Volhynia, and thanks to the help of Władysław I, Trojden I was able to put into the throne his own oldest son Bolesław, who assumed the name Yuri II (in honour of his maternal grandfather). In 1325 Trojden I and Siemowit I send a letter to the Pope determined the eastern border of their possession as reaching two miles from Grodno (Oppidi quod dictur Grodno, ... a terrarum nostrorum ad duas lencas posit). The aggressive policy pursued by Władysław I the Elbow-high (who wanted to reunite all the territories of Poland and Masovia) were a threat for Trojden I and his brothers, especially when Władysław I attacked and plundered Płock as a punishment for the 
Title: Trojden II of Płock
Content:  On 5 March 1424 along with his brothers Siemowit V, Casimir II and Władysław I, Trojden II attended the wedding and coronation of King Władysław II Jagiełło's third wife, Sophia of Halshany. After the death of their father on 21 January 1426 Trojden II and his brothers, not wanting to further weakened their positions and domains with subsequents divisions, decided to co-rule all their paternal inheritance. Another factor could be the difficult relationship with their mother, and after an eventual division of their domains they are forced to give her part of the lands as her dower. Despite the nominal co-rulership of the brothers, they administered separately their parts of the duchy. An analysis of the documents issued by Trojden II showed that he received Płock. On 8 September 1426 he and his brothers Siemowit V and Władysław I paid homage to the Polish King at Sandomierz. Trojden II died on 25 July 1427, unmarried and without issue. He was probably buried at Płock Cathedral.
Title: Duke of Masovia
Content:  Duke of Masovia (Książę Mazowsza) was a title born by the sons and descendants of the Polish Duke Bolesław III Wrymouth. In accordance with the last will and testament of Bolesław, upon his death his lands were divided into four to five hereditary provinces distributed among his sons, and a royal province of Kraków reserved for the eldest, who was to be High Duke of all Poland. This was known as the fragmentation of Poland. Subsequent developments lead to further splintering of the duchies. The following is a list of all rulers of the Duchy of Masovia and its parts. Although not all incumbents listed here had titular rights to the title of Duke of Masovia, they are all listed as such for simplicity's sake. Also take note that some of the dates are merely approximate and the ownership of certain lands might be disputed. Finally, this table does not include lands ruled by dukes of other parts of partitioned Poland or Wenceslaus II and Wenceslaus III.
Title: Duchy of Masovia
Content:  Poland, the Duchy of Masovia remained independent. Upon the death of Duke Boleslaus II in 1313, Masovia was divided among his sons: As neither Siemowit II nor Bolesław III of Płock left any heirs, Trojden's son Duke Siemowit III (1341&ndash;1381) was able to re-unite most of the Masovian lands under his rule; in 1351 he and his brother Casimir became vassals of the Polish kings, while the Bishopric of Płock had always been part of the Polish Archdiocese of Gniezno. Upon Siemowit's III death in 1381 however, Masovia was again partitioned between his sons: Since the Polish-Lithuanian Union of 1385, Masovia was localized between the joined Jagiellonian states. The Dukes of Masovia also ruled the Duchy of Belz until 

Question: Who is the mother of Trojden I, Duke of Masovia?
Answer: Gaudemunda of Lithuania.
Gaudemunda Sophia.