George Frederick Charles, Margrave of Brandenburg-Bayreuth
George Frederick Charles, Margrave of Brandenburg- Bayreuth( 19 June 1688 at Oberzulzbürg Castle, near Mühlhausen – 17 May 1735 in Bayreuth), was a German prince, member of the House of Hohenzollern, nominal Margrave of Brandenburg- Bayreuth- Kulmbach( 1708 – 35) and Margrave of Brandenburg- Bayreuth( 1726–35).
Frederick III, Margrave of Brandenburg-Ansbach
Frederick III, Margrave of Brandenburg- Ansbach( 1 May 1616, Ansbach – 6 September 1634, Nördlingen) was a German nobleman.
He was the eldest son of Joachim Ernst, Margrave of Brandenburg- Ansbach, who he succeeded in 1625.
He was killed at the Battle of Nördlingen in 1634 unmarried and without issue, meaning he was succeeded by his younger brother Albert II.
Frederick William, Margrave of Brandenburg-Schwedt
Frederick William of Brandenburg- Schwedt( 17 November 1700 – 4 March 1771) was a German nobleman.
In his lifetime, from 1711 to 1771, he held the titles Prince in Prussia and Margrave of Brandenburg, with the style Royal Highness.
He was made a knight of the Order of the Black Eagle.
In the 19th century he was retrospectively known by the title Margrave of Brandenburg- Schwedt, in order to differentiate his branch of the Hohenzollern dynasty.
He was the second owner of the Prussian secundogeniture of Brandenburg- Schwedt.
His parents were Philip William, Margrave of Brandenburg- Schwedt, and Princess Johanna Charlotte of Anhalt- Dessau.
He was the nephew of King Frederick I of Prussia.
John III, Margrave of Brandenburg-Salzwedel
John III, Margrave of Brandenburg-Salzwedel, nicknamed "John from Prague" (1244 in Prague – 1268) was the eldest son of Margrave Otto III and his wife, Beatrice of Bohemia.
After his father died in 1267, he ruled the Margraviate of Brandenburg jointly with his brother Otto V and his cousins Otto IV and Henry I.
John died during a tournament in 1268.
He was unmarried and childless.
Beatrice of Bohemia
Beatrice of Bohemia (1225–1290) was a daughter of King Wenceslaus I of Bohemia and his wife Kunigunde of Hohenstaufen.
She married Margrave Otto III and was the mother of:
Waldemar, Margrave of Brandenburg-Stendal
Waldemar the Great( – 14 August 1319), a member of the House of Ascania, was Margrave of Brandenburg- Stendal from 1308 until his death.
He became sole ruler of the Margraviate of Brandenburg upon the death of his cousin John V of Brandenburg- Salzwedel in 1317.
Waldemar is known as the last in the line of Ascanian margraves starting with Albert the Bear in 1157; he was only succeeded by his minor cousin Henry II, who died one year later.
Frederick, Margrave of Brandenburg-Bayreuth
Frederick, Margrave of Brandenburg- Bayreuth( May 10, 1711 in Weferlingen – February 26, 1763 in Bayreuth), was a member of the House of Hohenzollern and Margrave of Brandenburg- Bayreuth.
He was the eldest son of Georg Frederick Karl, nominal Margrave of Brandenburg- Bayreuth- Kulmbach, by his wife Dorothea of Schleswig- Holstein- Sonderburg- Beck.
Albert II, Margrave of Brandenburg
Albert II, Margrave of Brandenburg( – 25 February 1220) was a member of the House of Ascania.
He was Margrave of Brandenburg from 1205 until his death in 1220.
John V, Margrave of Brandenburg-Salzwedel
Margrave John
V of Brandenburg- Salzwedel, nicknamed" the Illustrious"( in Latin" Illustris"),( 1302 – 26 March 1317) was Margrave and co-ruler of Brandenburg from 1308 until his death.
His parents were Margrave Hermann," the Tall" of Brandenburg and Anne of Austria, a daughter of Emperor Albert I, Duke of Austria and King of Bohemia.
John married Catherine( d. 1327), a daughter of Duke Henry III of Glogau and Sagan.
John V died in 1317.
With his death, the Brandenburg- Salzwedel line of the House of Ascania died out.
Margaret of Brandenburg
Margaret of Brandenburg- Salzwedel( born ca. 1270 – died 1 May 1315) was a German noblewoman member of the House of Ascania and by her two marriages Duchess of Greater Poland( during 1293 – 1296), Queen of Poland( during 1295 – 1296) and Duchess of Saxe- Lauenburg( during 1302 – 1308).
She was the youngest child and second daughter of Albert III, Margrave of Brandenburg- Salzwedel and Matilda of Denmark, daughter of King Christopher I.

Question: Who is John Iii, Margrave Of Brandenburg-Salzwedel's maternal grandfather?
Answer: Wenceslaus I of Bohemia