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.
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.
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.
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.
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 William II, Duke of Schleswig-Holstein-Sonderburg-Beck
Frederick William II, Duke of Schleswig-Holstein-Sonderburg-Beck (18 June 1687 – 11 November 1749) was a Duke of Schleswig-Holstein-Sonderburg-Beck.
He served as Prussian field marshal and was appointed Governor of Berlin, but never filled the latter position.
Frederick William II was the eldest son of Duke Frederick Louis (1653–1728) and his wife Louise Charlotte of Schleswig-Holstein-Sonderburg-Augustenburg (1658–1740).
His siblings included Dorothea, Peter August, Charles Louis.
In 1728, Frederick William II succeeded his father as Duke of Beck.
After his death, he was succeeded by his son Frederick William III, who fell in battle in 1757.
The title was then inherited by Frederick William II's brother, Charles Louis.
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.
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.
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.
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 Frederick William Ii, Duke Of Schleswig-Holstein-Sonderburg-Beck's paternal grandfather?
Answer: August Philipp, Duke of Schleswig-Holstein-Sonderburg-Beck