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.
Christian VIII of Denmark
Christian VIII (18 September 1786 – 20 January 1848) was the King of Denmark from 1839 to 1848 and, as Christian Frederick, King of Norway in 1814.
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.
Friedrich, Duke of Schleswig-Holstein-Sonderburg-Glücksburg
Friedrich of Schleswig- Holstein- Sonderburg- Glücksburg( 23 October 1814 in Schleswig, Duchy of Schleswig – 27 November 1885 in Luisenlund, Schleswig- Holstein, Prussia) was the third Duke of Schleswig- Holstein- Sonderburg- Glücksburg.
Friedrich was the second- eldest son of Friedrich Wilhelm, Duke of Schleswig- Holstein- Sonderburg- Glücksburg and Princess Louise Caroline of Hesse- Kassel and an elder brother of Christian IX of Denmark.
Friedrich inherited the title of Duke of Schleswig- Holstein- Sonderburg- Glücksburg upon his childless brother Karl's death on 14 October 1878.
Caroline Amalie of Augustenburg
Caroline Amalie of Schleswig-Holstein-Sonderburg-Augustenburg (28 June 1796 – 9 March 1881) was queen consort of Denmark as the second spouse of King Christian VIII between 1839 and 1848.
Prince Frederick of Schleswig-Holstein-Sonderburg-Augustenburg
Prince Frederick Emil August of Schleswig-Holstein- Sonderburg- Augustenburg( Kiel, 23 August 1800 – Bayreuth, Germany, 2 July 1865), usually simply known by just his first name, Frederick," Prince of Noer", was a prince of the House of Schleswig- Holstein- Sonderburg- Augustenburg and a cadet- line descendant of the Danish royal house.
He was the second and youngest son of Louise Auguste of Denmark and Frederik Christian II, Duke of Schleswig- Holstein- Sonderburg- Augustenburg.
As such, he was close to succeed in the Danish throne.
He was the brother- in- law of King Christian VIII and nephew of King Frederik VI.
His elder brother, Christian August II, succeeded in 1814 as the Duke of Schleswig- Holstein- Sonderburg- Augustenburg.
After his second, morganatic union, he renounced the rights of succession to House of Augustenburg.
He was created Prince of Noer or Nør by Emperor Franz Joseph of Austria afterwards.
Prince Frederick died 1865 at Bayreuth.
John Adolphus, Duke of Schleswig-Holstein-Sonderburg-Plön
John Adolphus of Schleswig- Holstein- Sonderburg- Plön( or" Hans Adolf"; 8 April 1634, Ahrensbök – 2 July 1704 Ruhleben) was the second Duke of Schleswig- Holstein- Sonderburg- Plön, which had been created by a division of the Duchy of Schleswig- Holstein- Sonderburg.
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.
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.
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.

Question: Who is the father-in-law of Caroline Amalie Of Augustenburg?
Answer: Frederick