Elisabeth of Cleves, Countess of Schwarzburg-Blankenburg
Elisabeth of Cleves was the daughter of Adolph I, Duke of Cleves and Marie of Burgundy, Duchess of Cleves.
She married Count Henry XXVI of Schwarzburg- Blankenburg, on July 15, 1434.
Johann, Count of Cleves
Johann was last Count of Cleves, from 1347 through 1368.
Upon his death in 1368, the counties of Cleves and Count of Mark were united.
Johann was the youngest son of Dietrich VII, Count of Cleves and his second wife Margaret of Habsburg.
He succeeded in 1347 his brother Dietrich VIII, Count of Cleves who had died without sons.
He married Mechteld of Guelders( † 1384), daughter of Reginald II, Duke of Guelders, but the marriage remained childless.
After his death, the County of Cleves went to Adolf III of the Marck and so to the Counts of Marck.
Dietrich VII, Count of Cleves
Dietrich VII (1256–1305) was Count of Cleves from 1275 through 1305.
He was the son of Dietrich VI, Count of Cleves and his wife Aleidis von Heinsberg.
The County of Cleves  was a comital polity of the Holy Roman Empire in present Germany (part of North Rhine-Westphalia) and the Netherlands (parts of Limburg, Noord-Brabant and Gelderland).
Its rulers, called counts, had a special and privileged standing in the Empire.
The County of Cleves was first mentioned in the 11th century.
In 1417, the county became a duchy  and its rulers were raised to the status of Dukes.
Its history is closely related to that of its neighbours: the Duchies of Jülich, Berg and Guelders and the County of Mark.
In 1368, Cleves and Mark were united.
In 1521 Jülich, Berg, Cleves and Mark formed the United Duchies of Jülich-Cleves-Berg.
The territory was situated on both sides of the river Rhine, around its capital Cleves and roughly covering today's districts of Cleves, Wesel and the city of Duisburg.
Adolph II of the Marck
Adolph II of the Marck( died 19/20 October 1347, Fröndenberg) was Count of the Marck.
He was the eldest son of Engelbert II of the Mark and Mechtild of Arenberg.
Adolph was betrothed to Irmgard of Cleves, daughter of Otto, Count of Cleves and his( second) wife Mechtild of Virneburg.
After obtaining a papal dispensation Adolf was allowed to marry Margaret of Cleves, the daughter of Dietrich VIII, Count of Cleves and Margaret of Guelders.
Adolph and Margaret of Cleves had seven children:
Karl Harst
Karl Harst( fl. 1540) was a sixteenth- century diplomat from the German Duchy of Cleves.
He was the Duke of Cleves' representative in London during the marriage of Henry VIII of England and his fourth wife, Anne of Cleves.
Dietrich VIII, Count of Cleves
Dietrich VIII( – 7 July 1347) was a German nobleman.
He was Count of Cleves from 1310 through 1347.
Dietrich was the son of Dietrich VII, Count of Cleves and his second wife Margaret of Habsburg.
He succeeded in 1310 his half- brother Otto, Count of Cleves who had died without sons.
Dietrich VIII married twice:
He was succeeded by his brother John.< br>
When his brother also died without a son, the County of Cleves went to his daughter's son Adolph III of the Marck and so to the Counts of Marck.
Adolph I, Duke of Cleves
Adolph I of Cleves( 2 August 1373 – 23 September 1448) was the second Count of Cleves and the fourth Count of Mark.
Otto, Count of Cleves
Otto (1278 – Horstmar, October 29, 1310) was Count of Cleves from 1305 through 1310.
Otto was the eldest son of Dietrich VII, Count of Cleves (1256–1305) and his first wife Margaret of Guelders.<br>
His first marriage was to Adelheid van der Marck, daughter of Engelbert I, Count of the Mark and secondly to
Mechteld von Virneburg, a niece of Heinrich II of Virneburg.<br
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They had one daughter Irmgard of Cleves, who married Adolph II of the Marck and later John IV of Arkel.
When he died in 1310 he was succeeded by his half-brother Dietrich VIII.
John I, Duke of Cleves
John I, Duke of Cleves, Count of Mark( 16 February 1419 – 5 September 1481) was Duke of Cleves and Count of Mark.
Irmgard of Cleves
Irmgard of Cleves( also known as" Irmengard von Kleve") was the wife of John IV, Lord of Arkel.
Born in 1307, she was the only daughter of Otto, Count of Cleves and his wife, Mechteld von Virneburg.
Her father, Count Otto died shortly after her birth.

Question: Who is Otto, Count Of Cleves's paternal grandfather?
Answer: Dietrich VI, Count of Cleves