Henry I, Count of Holstein-Rendsburg
Henry I, Count of Holstein- Rendsburg( 1258–1304) was the first Count of Holstein- Rendsburg.
Albert II, Count of Holstein-Rendsburg
Albert II of Holstein( – 28 September 1403 in Dithmarschen( Ditmarsh)) was the ruling Count of Holstein- Rendsburg from his father's death, in 1381 or 1384, until 1397.
From 1397 until his death, he was Count of Holstein- Segeberg.
Gerhard III, Count of Holstein-Rendsburg
Gerhard III of Holstein-Rendsburg (– 1 April 1340), sometimes called Gerhard the Great, and in Denmark also known as "Count Gert" or "den kullede grevethe bald count"), was a German prince from the Schauenburg family who ruled Holstein-Rendsburg and a large part of Denmark during the interregnum of 1332–40.
His father was Henry I, Count of Holstein-Rendsburg (c. 1258 – 5 August 1304).
Gerhard inherited his part of the county of Holstein as a boy.
While he was a young man he enlarged his inheritance by manoeuvring out his relatives and by his conquest of other parts of Holstein.
These actions made him a powerful local prince.
In these years he also was employed as a paid "condottiere" for neighbouring kings including King Eric VI of Denmark.
He often partnered with his Holstein cousin Count John III, Count of Holstein-Plön.
In 1325 Gerhard began his career in the North by taking over the guardianship for his minor nephew Duke Valdemar of Schleswig.
This position made him a possible ally of the dissatisfied Danish magnates and 1326 he dethroned King Christopher II together with the Danish rebels.
From then until his death he had a major influence on Danish politics.
He placed his nephew, Valdemar, on the Danish throne, was made the regent of Denmark and at the same time he secured the separation of Schleswig from Denmark by the so-called Constitutio Valdemariana which formed the basis for the long-standing German influence on South Jutland.
His inability to bring peace and order led to rebellions and a conflict with Count Johan.
As a result, in 1329 Gerhard replaced Valdemar with Christopher II as the puppet king.
After the death of Christopher in 1332, Gerhard effectively took over as ruler of Denmark.
From 1332 to 1340 Count Gerhard was the real ruler of what had been Denmark being the lord of both Jutland and Funen, leaving the rest of the country to Johan.
However his position was insecure because he had numerous creditors who had financed his armies and therefore were able to influence him.
The result was a growing opposition against the foreign rule within the Danish gentry that had earlier supported him.
Peasant rebellions and lawlessness at sea led to increasing chaos and
Gerhard was put under pressure from the neighbouring German states which now supported Christopher's son Valdemar (afterwards to be king Valdemar IV).
Gerhard seems to have prepared to compromise in return for his outstanding debts being dealt with but before a solution was the reached in the spring of 1340 he started a new campaign against rebels in North Jutland.
During the campaign he was slain in the town of Randers by the Danish squire Niels Ebbesen who had entered his bedroom together with some of his men.
His death meant the end of Holstein rule in Denmark.
Gerhard's two sons gave up their right to Gerhard's titles in Denmark and Valdemar IV was subsequently placed on the Danish throne.
Because of his influential role in Danish politics Gerhard has been the subject of controversy as to his legacy.
In Denmark he is traditionally regarded as a scoundrel and a “German tyrant” and his murder has been viewed as one of the highlights of Danish history, having inspired Danish poets and authors as late as during the German occupation of Denmark 1940–1945.
In the Ditmarshes (Dithmarschen) in which he ravaged he also seems to be unfavourable viewed.
In Holstein however he has been regarded as a national hero.
From contemporary sources he appears to have been energetic and brutal warrior, yet deeply religious.
Henry II, Count of Holstein-Rendsburg
Count Henry II of Holstein- Rendsburg( nickname" Iron Henry"; –) was count of Holstein- Rendsburg and pledge lord of Southern Schleswig.
He ruled jointly with his younger brother, Count Nicholas( d. 1397).
Gerhard I, Count of Holstein-Itzehoe
Gerhard I, Count of Holstein- Itzehoe( 1232 – 21 December 1290) was the only count of Holstein- Itzehoe.
Adolph V, Count of Holstein-Segeberg
Adolph V, Count of Holstein- Segeberg( – 1308) was the ruling count of Holstein- Kiel from 1263 to 1273 and of Holstein- Segeberg from 1273 until his death.
Gerhard VII, Count of Holstein-Rendsburg
Gerhard VII, Count of Holstein- Rendsburg( 1404 – 24 July 1433 in Emmerich am Rhein) was Count of Holstein- Rendsburg and by claim also Duke of Schleswig, as Gerhard III.
He was the youngest son of Gerhard VI and his wife Elizabeth of Brunswick.
Albert IV, Duke of Mecklenburg
Albert IV, Duke of Mecklenburg (before 1363 - 24/31 December 1388) was co-regent of Mecklenburg from 1383 to 1388.
He was the son of the Duke Henry III of Mecklenburg and Ingeborg of Denmark.
Albert was also a claimant to the Danish throne after the death of King Valdemar IV, but Olaf II succeeded instead.
After his father Henry died in 1383, Albert ruled Mecklenburg jointly with his uncles Albert III and Magnus I and his cousin John IV.
He was married to Elisabeth of Holstein, the daughter of Nicholas, Count of Holstein-Rendsburg and died in December 1388.
In 1404 his widow Elisabeth married Duke Eric V of Saxe-Lauenburg.
Nicholas, Count of Holstein-Rendsburg
Nicholas, Count of Schauenburg and Holstein-Rendsburg (also known as " Claus of Holstein"; 1321 – 8 May 1397 in Itzehoe) was a titular Count of Schauenburg.
Together first with his brother and then with his nephews, Nicholas was the co-ruling Count of Holstein-Rendsburg from 1340 until his death.
In 1390 Nicholas and his nephews inherited Holstein-Kiel, which itself included former Holstein-Plön through reversion in 1350.
So except of Holstein-Pinneberg Nicholas and his nephews had united all of Holstein.
He was also co-ruler of Schleswig from 1375 to 1386.
He was thus a leading member of the House of Schauenburg and an influential figure in the area north of the Elbe.
He was the second son of Count Gerhard III of Holstein-Rendsburg and his wife, Sophia of Werle.
He ruled Schleswig jointly with his elder brother Henry II from 1375 to 1384, thereafter alone.
In 1386, he abdicated as Duke of Schleswig in favour of Henry II's son Gerhard VI of Holstein-Rendsburg, who was confirmed as Gerhard II as Duke of Schleswig by King Olaf II of Denmark.
In 1354, he married Elisabeth, the daughter of Duke William II of Brunswick and Lüneburg, Prince of Lunenburg.
She was the widow of Otto of Saxe-Wittenberg, a son of Rudolph I.
They had one daughter:
In 1362, Nicholas engaged his daughter to Prince Haakon, who later became King Haakon VI of Norway.
However, the engagement was broken off for political reasons in 1363 and Haakon married Queen Margaret I of Denmark instead.
Nicholas died in 1397 and was buried in Itzehoe.
His nephew Gerhard VI acted as guardian for his underage daughter Elisabeth.
After Nicholas' death
his co-ruling nephews Albert II and the elder Gerhard VI partitioned Holstein-Segeberg as a secundogeniture for Albert from Holstein-Rendsburg.
Gerhard VI then continued ruling Holstein-Rendsburg as the sole count.
Henry IV, Count of Holstein-Rendsburg
Henry IV, Count of Holstein- Rendsburg( 1397 – 28 May 1427) was Count of Holstein- Rendsburg and Duke of Schleswig from 1404 until his death.

Question: Who is Nicholas, Count Of Holstein-Rendsburg's paternal grandfather?
Answer: Henry I, Count of Holstein-Rendsburg