Question: Who is Alexandra Of Lithuania's father-in-law?

Knowledge 1: Alexandra of Lithuania
Alexandra (died 20 April 1434 in Płock) was the youngest daughter of Algirdas, Grand Duke of Lithuania, and his second wife, Uliana of Tver.Though Alexandra's exact date of birth is not known, it is thought that she was born in the late 1360s or early 1370s.In 1387, she married Siemowit IV, Duke of Masovia, and bore him thirteen children. [SEP] Knowledge 2: Siemowit IV, Duke of Masovia
Siemowit IV (Ziemowit IV), also known as Siemowit IV the Younger(pl: "Siemowit IV Młodszy"; ca. 1353/1356 – 21 January 1426), was a Polish prince member of the House of Piast from the Masovian branch, from 1373/74 Duke of Rawa, and after the division of the paternal inheritance between him and his brother in 1381, ruler over Rawa, Płock, Sochaczew, Gostynin, Płońsk and Wizna, since 1386 hereditary Polish vassal, since 1388 ruler over Belz, during 1382–1401 he lost Wizna and during 1384–1399 and 1407–1411 he lost Zawkrze, during 1384–1399 he lost Płońsk, taken by the Teutonic Order.He was the second son of Siemowit III, Duke of Masovia and his first wife Euphemia, daughter of Nicholas II of Opava.Already during his father's lifetime, Siemowit IV received his own district, Rawa Mazowiecka (ca. 1373/74), and as a result of the partition of Masovia between him and his older brotherJanuszI after the death of their father on 16 June 1381, Siemowit IV finally obtain the totality of his domains:Rawa, Płock, Sochaczew, Gostynin, Płońsk and Wizna.
Knowledge 1: Alexandra of Lithuania
Alexandra (died 20 April 1434 in Płock) was the youngest daughter of Algirdas, Grand Duke of Lithuania, and his second wife, Uliana of Tver.Though Alexandra's exact date of birth is not known, it is thought that she was born in the late 1360s or early 1370s.In 1387, she married Siemowit IV, Duke of Masovia, and bore him thirteen children. [SEP] Knowledge 2: Barthold A. Butenschøn Sr.
Hans Barthold Andresen Butenschøn( 27 December 1877 – 28 November 1971) was a Norwegian businessperson.He was born in Kristiania as a son of Nils August Andresen Butenschøn and Hanna Butenschøn, and grandson of Nicolay Andresen.Together with Mabel Anette Plahte( 1877 – 1973, a daughter of Frithjof M. Plahte) he had the son Hans Barthold Andresen Butenschøn Jr. and was through him the father- in- law of Ragnhild Butenschøn and grandfather of Peter Butenschøn.Through his daughter Marie Claudine he was the father- in- law of Joakim Lehmkuhl, through his daughter Mabel Anette he was the father- in- law of Harald Astrup( a son of Sigurd Astrup) and through his daughter Nini Augusta he was the father- in- law of Ernst Torp.He took commerce school and agricultural school.He was hired in the family company N. A. Andresen& Co, and became a co-owner in 1910.He eventually became chief executive officer.The bank changed its name to Andresens Bank in 1913 and merged with Bergens Kreditbank in 1920.The merger was dissolved later in the 1920s.He was also a landowner, owning Nedre Skøyen farm and a lot of land in Enebakk.He chaired the board of Nydalens Compagnie from 1926, having not been a board member before that.He also chaired the supervisory council of Forsikringsselskapet Viking and Nedre Glommen salgsforening, and was a supervisory council member of Filharmonisk Selskap.He was a member of the gentlemen's club SK Fram since 1890, and was proclaimed a lifetime member in 1964.He was buried in Enebakk.
Knowledge 1: Alexandra of Lithuania
Alexandra (died 20 April 1434 in Płock) was the youngest daughter of Algirdas, Grand Duke of Lithuania, and his second wife, Uliana of Tver.Though Alexandra's exact date of birth is not known, it is thought that she was born in the late 1360s or early 1370s.In 1387, she married Siemowit IV, Duke of Masovia, and bore him thirteen children. [SEP] Knowledge 2: Ogawa Mataji
Viscount was a general in the early Imperial Japanese Army.He was also the father- in- law of Field Marshal Gen Sugiyama.

Answer: Siemowit III, Duke of Masovia