Joanna, Duchess of Durazzo
Joanna of Durazzo( 1344 – 20 July 1387) was the eldest daughter and eldest surviving child of Charles, Duke of Durazzo, and his wife, Maria of Calabria.
She succeeded as duchess on the death of her father in 1348 when she was only a child of four years old.
Joanna was a member of the House of Anjou- Durazzo.
She reigned as Duchess of Durazzo from 1348- 1368.
She married twice; firstly to Louis of Navarre and then to Robert IV of Artois, Count of Eu.
William I, Count of Eu
William I, Count of Eu( 978- after 1057), illegitimate son of Richard I, Duke of Normandy.
Count of Eu and Count of Hiémois.
William succeeded his nephew, Gilbert, as Count of Eu and Hiémois after his murder in 1040.
William rebelled against his half- brother Richard II, Duke of Normandy, and was captured by Raoul d’ Ivry and imprisoned by Turquetil of Harcourt, former governor of William the Conqueror ..
He escaped five years later and, eventually, was pardoned by Richard and given leave to marry into the Harcourt family.
William married Lesceline, daughter of Turquetil.
William and Lesceline had three children: William ’s son, Robert, succeeded him as count of Eu.
Robert IV of Artois, Count of Eu
Robert IV of Artois (1356 – July 20, 1387), son of John of Artois, Count of Eu and Isabeau of Melun, was Count of Eu from April to July 1387.
About 1376, he married Joanna of Durazzo, daughter of Charles, Duke of Durazzo.
Robert IV inherited the County of Eu on April 6, 1387 along with Saint-Valery and Ault, however, in Naples at the time, he never learned of his father's death.
He and his wife were poisoned whilst staying at Castel dell'Ovo on July 20, 1387 on the orders of Joanna's own sister Margaret, Queen Regent of Naples.
Robert and Joanna were buried in the church of San Lorenzo Maggiore in Naples.
The marriage of Robert and Joanna had remained childless.
Robert was succeeded in Eu by his younger brother Philip of Artois, Count of Eu.
William II, Count of Eu
William II, Count of Eu, feudal baron of Hastings( d. circa 1095) was a first generation Anglo- Norman nobleman, Count of Eu and rebel.
Philip of Artois, Count of Eu
Philip of Artois( 1358 – 16 June 1397, Micalizo), son of John of Artois, Count of Eu, and Isabeau of Melun, was Count of Eu from 1387 until his death, succeeding his brother Robert.
Philip was a gallant and energetic soldier.
In 1383, he captured the town of Bourbourg from the English.
He went on a pilgrimage to the Holy Land, and was imprisoned there by Barquq, the Sultan of Egypt, being released through the mediation of Jean Boucicaut and the Venetians.
In 1390, he joined the unsuccessful expedition of Louis II, Duke of Bourbon, against Mahdia.
In 1392, he was created Constable of France.
On 27 January 1393 he married Marie( 1367 – 1434), daughter of John, Duke of Berry.
They had four children:
As a prominent Crusader, he was one of the French contingent sent to take part in the Battle of Nicopolis.
He was captured in the battle, and subsequently died in captivity.
Philip of Artois
Philip of Artois( 1269 – 11 September 1298) was the son of Robert II of Artois, Count of Artois, and Amicie de Courtenay.
He was the Lord of Conches, Nonancourt, and Domfront.
He married Blanche of Brittany, daughter of John II, Duke of Brittany, and had the following children:
He served under his father at the Battle of Furnes, where he was wounded.
He never recovered, and died of the effects over a year later.
He was buried in the now- demolished church of the Couvent des Jacobins in Paris.
His premature death led to a legal battle later, when Artois was left to his sister Mahaut rather than his son Robert.
John of Artois, Count of Eu
John of Artois (29 August 1321 – 1387), called "sans Terre" (Lackland), was the son of Robert III of Artois and Joan of Valois.
The confiscation of his father's goods for attempted fraud in 1331 had left him without an inheritance.
In 1352, he was created Count of Eu, a title earlier forfeited at the execution of the previous holder, Raoul II of Brienne.
He was badly wounded at the Battle of Poitiers on 19 September 1356, and was captured there by the English.
Enormously rich his ransom was sold to the Black Prince by his captor Élie de Pommiers for 30,000 old écus.
He married Isabeau of Melun (1328–1389), daughter of John I of Melun, Count of Tancarville, on 11 July 1352 and had the following issue:
Joan of Valois, Countess of Beaumont
Joan of Valois (1304–1363) was the daughter of Charles of Valois and his second wife Catherine I of Courtenay, titular empress of Constantinople.
Half sister to Philip VI of Valois, in around 1320 she married Robert III of Artois, Count of Beaumont-le-Roger and seigneur of Conches.
They had five known children:
Robert III of Artois had attempted to recover the title of count of Artois, which had been taken from him by his aunt Mahaut of Artois, but was condemned and exiled in 1331 for making and presenting forged documents in the process of filing against her.
Joan of Valois and their children were therefore imprisoned by order of her half-brother Philip VI.
William Bourchier, 1st Count of Eu
William Bourchier, 1st Count of Eu( 1374- 28 May 1420), was an English knight created by King Henry V 1st Count of Eu, in Normandy.
Charles of Artois, Count of Eu
Charles of Artois( 1394 – 25 July 1472), son of Philip of Artois, Count of Eu and Marie of Berry, was Count of Eu from December 1397 until his death 74 years later.
He was taken prisoner by the English at the Battle of Agincourt on 25 October 1415, and was not released until 1438.
In 1448, he married Jeanne of Saveuse( died 1449) and on 23 September 1454, Helene of Melun( d. 1473), but he had no children.
He was appointed Lieutenant of the King in Normandy and Guyenne, as well as Governor of Paris, during the War of the Public Weal in 1465.
He was succeeded by his nephew John II, Count of Nevers.

Question: Who is Robert Iv Of Artois, Count Of Eu's paternal grandfather?
Answer: Robert III of Artois