Prince Karl Anton August of Schleswig-Holstein-Sonderburg-Beck
Prince Karl Anton August of Schleswig -Holstein- Sonderburg- Beck( 10 August 1727, in Marburg – 12 September 1759, in Stettin) was the son of Peter August, Duke of Schleswig- Holstein- Sonderburg- Beck and Princess Sophie of Hesse- Philippsthal.
Frederick Ferdinand, Duke of Anhalt-Köthen
Frederick Ferdinand of Anhalt-Köthen (25 June 1769, Pless – 23 August 1830, Köthen) was a German prince, Ascanian ruler of the principality of Anhalt-Pless and, from 1818, of the duchy of Anhalt-Köthen.
He was the second son of Frederick Erdmann, Prince of Anhalt-Pless, and his wife, Louise Ferdinande, daughter of Henry Ernest, Count of Stolberg-Wernigerode.
Friedrich Karl Ludwig, Duke of Schleswig-Holstein-Sonderburg-Beck
Friedrich Karl Ludwig of Schleswig- Holstein- Sonderburg- Beck( 20 August 1757 – 24 April 1816) was the ninth and penultimate Duke of Schleswig- Holstein- Sonderburg- Beck.
Friedrich Karl Ludwig was the son of Prince Karl Anton August of Schleswig- Holstein- Sonderburg- Beck and his wife Countess Charlotte of Dohna- Schlodien.
Friedrich Wilhelm, Duke of Schleswig-Holstein-Sonderburg-Glücksburg
Friedrich Wilhelm, Duke of Schleswig-Holstein-Sonderburg-Glücksburg (4 January 1785 – 17 February 1831) inherited the title of Duke of Schleswig-Holstein-Sonderburg-Beck in 1816.
He subsequently changed his title to Duke of Schleswig-Holstein-Sonderburg-Glücksburg in 1825 and founded a line that includes the Royal Houses of Denmark, Greece, Norway, and the Commonwealth realms.
Frederick Louis, Duke of Schleswig-Holstein-Sonderburg-Beck
Frederick Louis of Holstein- Sonderburg- Beck( 6 April 1653 – 7 March 1728) was a Duke of Schleswig- Holstein- Sonderburg- Beck and field marshal of the Prussian Army.
He was the son of August Philipp, Duke of Schleswig- Holstein- Sonderburg- Beck and Countess Marie Sibylle of Nassau- Saarbrücken.
Frederick William I, Duke of Schleswig-Holstein-Sonderburg-Beck
Frederick William I, Duke of Duke of Schleswig- Holstein- Sonderburg- Beck( German:" Friedrich Wilhelm I. von Schleswig- Holstein- Sonderburg- Beck"; 2 May 1682 – 16 June 1719) was a son of Duke August and his wife, Philippa Louisa of Lippe- Buckburg.
He succeeded his father as Duke of Beck in 1689.
He converted to Roman Catholicism and joined the Army of the Holy Roman Empire.
He died of his wounds in the Battle of Francavilla in Sicily in 1719.
Since he had no male heir, he was succeeded as Duke of Beck by his uncle Frederick Louis.
Peter August, Duke of Schleswig-Holstein-Sonderburg-Beck
Peter August Friedrich, Duke of Schleswig-Holstein-Sonderburg-Beck (7 December 1697 – 22 March 1775) was a Duke of Schleswig-Holstein-Sonderburg-Beck.
He was the fifth and youngest son of Frederick Louis, Duke of Schleswig-Holstein-Sonderburg-Beck and his wife Duchess Louise Charlotte of Schleswig-Holstein-Sonderburg-Augustenburg.
Born in Königsberg, Brandenburg-Prussia, Peter August became Governor General of Reval (Tallinn), Governor of Estonia, and a Field Marshal in the Russian Imperial Army.
He died in Reval.
He was only the "titular" duke, because he did not inherit the domain of Beck.
It had been inherited by his father's older brother, Duke August (1652–1689), and nephew Frederick William I (1682–1719), and was then sold by the latter's widow to Peter August's older brother, Duke Frederick William II (1687–1749), in 1732.
But he re-sold it in 1745 to Baroness Magdalena von Ledebur-Königsbrück.
Thus, by the time that Peter August became the head of this cadet branch of the Danish royal dynasty, he was "Duke of Schleswig-Holstein-Sonderburg-Beck" in name only.
He is the male line ancestor of Margrethe II of Denmark, Harald V of Norway and Charles, Prince of Wales.
August, Duke of Schleswig-Holstein-Sonderburg-Beck
August, Duke of Schleswig- Holstein- Sonderburg- Beck( 13 February 1652 – 26 September 1689 in Bonn) was a German nobleman.
From 1675 until his death, he was the ruling Duke of Schleswig- Holstein- Sonderburg- Beck.
He was the second duke of this appanage.
August Philipp, Duke of Schleswig-Holstein-Sonderburg-Beck
August Philipp, Duke of Schleswig -Holstein- Sonderburg- Beck( 11 November 1612 – 6 May 1675) was a Danish- German prince and member of the House of Oldenburg.
After acquiring the estate of Beck in Westfalen in 1646, he took the title of Duke of Schleswig- Holstein- Sonderburg- Beck.
Princess Luise of Schleswig-Holstein-Sonderburg-Beck
Luise, Princess of Anhalt-Pless (née Princess Maria Dorothea Henriette Luise of Schleswig-Holstein-Sonderburg-Beck; 28 September 1783 – 24 November 1803) was a member of the Danish royal family and, as the first wife of Frederick Ferdinand, Prince of Anhalt-Pless, the princess consort of Anhalt-Pless.

Question: Who is Princess Luise Of Schleswig-Holstein-Sonderburg-Beck's father-in-law?