Princess Victoria Adelaide of Schleswig-Holstein
Princess Victoria Adelaide of Schleswig-Holstein-Sonderburg-Glücksburg (31 December 1885 – 3 October 1970) was the consort of Charles Edward, Duke of Saxe-Coburg and Gotha and is the maternal grandmother of Carl XVI Gustaf of Sweden.
Joachim Ernest, Duke of Schleswig-Holstein-Sonderburg-Plön
Joachim Ernest of Schleswig-Holstein- Sonderburg- Plön( 29 August 1595 – October 5, 1671), also" Joachim Ernest of Schleswig- Holstein- Plön", was the first Duke of Schleswig- Holstein- Sonderburg- Plön, which emerged from a division of the Duchy of Schleswig- Holstein- Sonderburg.
Princess Alexandra Victoria of Schleswig-Holstein-Sonderburg-Glücksburg
Princess Alexandra Victoria of Schleswig-Holstein- Sonderburg- Glücksburg( 21 April 1887 – 15 April 1957) was a daughter of Friedrich Ferdinand, Duke of Schleswig- Holstein and his wife Princess Karoline Mathilde of Schleswig- Holstein- Sonderburg- Augustenburg.
Johann Leopold, Hereditary Prince of Saxe-Coburg and Gotha
Johann Leopold, Hereditary Prince of Saxe- Coburg and Gotha( Johann Leopold William Albert Ferdinand Victor; 2 August 1906 – 4 May 1972) was the eldest son of Charles Edward, Duke of Saxe- Coburg and Gotha, and Princess Victoria Adelaide of Schleswig- Holstein- Sonderburg- Glücksburg.
Charles Edward, Duke of Saxe-Coburg and Gotha
Charles Edward (baptised Leopold Charles Edward George Albert, ; 19 July 1884 – 6 March 1954) was the last reigning duke of Saxe-Coburg and Gotha from 30 July 1900 until 1918.
A male-line grandson of Queen Victoria and Prince Albert
, he was also until 1919 a Prince of the United Kingdom and from birth held the British titles of Duke of Albany, Earl of Clarence and Baron Arklow.
Charles Edward was a controversial figure in the United Kingdom due to his status as the sovereign Duke of Saxe-Coburg and Gotha, which was part of the German Empire, during World War I. On 14 November 1918, however, after a revolution in Germany, he was forced to abdicate as Duke of Saxe-Coburg and Gotha and lost his rights to the ducal throne.
In 1919, Charles Edward was deprived of his British peerages, his title of Prince and "Royal Highness" and his British honours for having fought in the German Army (eventually as a General) during WWI; he was labelled a "traitor peer".
Charles Edward later joined the Nazi Party as well as the Sturmabteilung (SA, or Brownshirts), where he reached the position of Obergruppenführer.
Charles Edward served in a number of positions in Nazi Germany in the 1930s and 1940s, including President of the German Red Cross from 1933–45.
He was the maternal grandfather of King Carl XVI Gustaf of Sweden and the younger brother of Princess Alice, Countess of Athlone.
After paying the fines imposed by the denazification court and losing properties to the Soviet army, he died in poverty in 1954.
Princess Helena Adelaide of Schleswig-Holstein-Sonderburg-Glücksburg
Princess Helena Adelaide of Schleswig-Holstein- Sonderburg- Glücksburg( 1 June 1888- 30 June 1962) was the third eldest daughter of Friedrich Ferdinand, Duke of Schleswig- Holstein and his wife Princess Karoline Mathilde of Schleswig- Holstein- Sonderburg- Augustenburg.
She was a princess of Denmark through her marriage within the House of Schleswig- Holstein- Sonderburg- Glücksburg to Prince Harald of Denmark.
Princess Helena was a Nazi sympathiser during World War II and was after the war exiled from Denmark, but eventually allowed to return, where she died.
Albert, Duke of Schleswig-Holstein
Albert, Duke of Schleswig- Holstein( Albert John Charles Frederick Alfred George; 26 February 1869 – 27 April 1931), was a grandson of Queen Victoria.
He was the second son of Victoria's daughter, Princess Helena, by her husband Prince Christian of Schleswig- Holstein.
He was the head of the House of Oldenburg and also the House of Schleswig- Holstein- Sonderburg- Augustenburg and the Duke of Schleswig- Holstein between 1921 and 1931.
Joachim Frederick, Duke of Schleswig-Holstein-Sonderburg-Plön
Joachim Frederick of Schleswig-Holstein- Sonderburg- Plön( 9 May 1668, Magdeburg – 25 January 1722, Plön), also known as Joachim Frederick of Schleswig- Holstein- Plön, was the third Duke of Schleswig- Holstein- Plön, a dukedom created by the division of the Duchy of Schleswig- Holstein- Sonderburg.
Princess Marie Alexandra of Schleswig-Holstein
Princess Marie Alexandra of Schleswig-Holstein -Sonderburg- Glücksburg, since 1941 of Schleswig- Holstein( Marie Alexandra Caroline- Mathilde Viktoria Irene; 9 July 1927, Schloss Louisenlund, Schleswig, Schleswig- Holstein, Germany – 14 December 2000, Friedrichshafen, Baden- Württemberg, Germany) was a member of the House of Schleswig- Holstein- Sonderburg- Glücksburg.
Marie Alexandra was the fourth and youngest child of Wilhelm Friedrich, Duke of Schleswig- Holstein and his wife Princess Marie Melita of Hohenlohe- Langenburg.
Her older brother Peter was the Duke of Schleswig- Holstein and Head of the House of Oldenburg from 10 February 1965 until his death on 30 September 1980.
Friedrich Ferdinand, Duke of Schleswig-Holstein
Friedrich Ferdinand of Schleswig- Holstein- Sonderburg- Glücksburg( 12 October 1855 – 21 January 1934) was the fourth Duke of Schleswig- Holstein- Sonderburg- Glücksburg and became Duke of Schleswig- Holstein in 1931.

Question: Who is Princess Victoria Adelaide Of Schleswig-Holstein's sibling-in-law?