Albert, Count of Nassau-Dillenburg
Albert, Count of Nassau-Dillenburg (1 November 1596 in Dillenburg – 16 June 1626 in Quakenbrück) was a son of Count George of Nassau-Dillenburg and his first wife, Anna Amalia of Nassau-Saarbruucken.
After his father died in 1623, he ruled Nassau-Dillenburg jointly with his elder brother Louis Henry until Albert died himself in 1626.
William II, Prince of Nassau-Dillenburg
William II, Prince of Nassau- Dillenburg( 28 August 1670 – 21 September 1724 in Dillenburg) was the ruler( i.e. Fürst) of Nassau- Dillenburg from 1701 until his death.
His parents were Henry, Prince of Nassau- Dillenburg( 1641 – 1701) and his wife Princess Dorothea Elisabeth of Legnica- Brzeg( 1646 – 1691).
Elisabeth of Nassau-Dillenburg, Countess of Wied
Elisabeth of Nassau-Dillenburg (1 December 1488 – 3 June 1559 in Dillenburg) was a member of the House of Nassau.
She was a daughter of John V of Nassau-Dillenburg and his wife Elisabeth of Hesse-Marburg.
Her brothers were Henry III of Nassau-Breda, John of Nassau-Vianden-Dietz, Ernest of Nassau and William the Rich.
Her sister was Maria of Nassau.
Johanna of Nassau-Dillenburg
Johanna of Nassau-Dillenburg  was a daughter of Count John IV of Nassau and his wife Maria of Loon-Heinsberg.
On 14 October 1464, she married Philip I, Count of Waldeck.
They had one son: Henry VIII.
Henry III of Nassau-Breda
Count Henry III of Nassau- Dillenburg- Dietz( 12 January 1483, Siegen – 14 September 1538, Breda), Lord( from 1530 Baron) of Breda, Lord of the Lek, of Dietz, etc. was a count of the House of Nassau.
He was the son of Count John V of Nassau- Dillenburg and Elisabeth of Hesse- Marburg.
His younger brother was William I, Count of Nassau- Dillenburg( the father of William the Silent).
Maria of Nassau-Dillenburg
Maria of Nassau- Dillenburg( 1568- 1625) was a daughter of Count John VI" the Elder" of Nassau- Dillenburg and his first wife, Countess Elisabeth of Leuchtenberg.
Maria married
John Louis I, Count of Nassau- Wiesbaden- Idstein in 1588 and was the mother of:
Christian, Prince of Nassau-Dillenburg
Christian, Prince of Nassau- Dillenburg( 12 August 1688 at Dillenburg Castle – 28 August 1739 in Straßebersbach, now part of Dietzhölztal) was the last ruler( i.e. Fürst) of Nassau- Dillenburg from the line that had started in 1606 with George, Count of Nassau- Dillenburg.
Adolf of Nassau (1540–1568)
Adolf of Nassau (Dillenburg, 11 July 1540 – Heiligerlee, 23 May 1568) was a count of Nassau, also known as Adolphus of Nassau.
He was the fourth son and sixth child of William I, Count of Nassau-Dillenburg and Juliana of Stolberg.
He was the second youngest brother of William the Silent.
Maria of Loon-Heinsberg
Maria of Loon-Heinsberg (1426 – 20 April 1502) was the daughter of John II of Loon, Lord of Jülich, Heinsberg and Löwenberg.
Her mother was the second wife of John II, Countess Margaret of Solms-Braunfels.
Maria died on 20 April 1502 as the last member of the house of Loon-Heinsberg and is buried with her husband in the mausoleum of Engelbert
I of Nassau in the Church of Our Lady at the Market Square in Breda.
William I, Count of Nassau-Dillenburg
William I, Count of Nassau- Dillenburg( nicknamed" William the Rich",; 10 April
1487 – 6 October 1559) was a count of Nassau- Dillenburg from the House of Nassau.
His nickname" the Rich" refers to him having many children.
However, he owned a number of counties: Nassau- Dillenburg, Nassau- Siegen, Nassau- Dietz and Vianden.
William was born in Dillenburg as the younger son of Count John V of Nassau- Dillenburg and Landgravine Elisabeth, daughter of Landgrave Henry III of Hesse- Marburg and Anna of Katzenelnbogen.
He was the brother of count Henry III of Nassau- Breda and the father of William I of Orange.
His eldest son William the Silent inherited the principality of Orange in Southern France from his cousin René of Chalon, as well as the vast properties of the House of Nassau- Dillenburg in the Netherlands from his father, which Engelbert I of Nassau had received by marriage in 1403.
The early House of Orange- Nassau descends from William I., the Silent, while the later House of Orange- Nassau( and the Dutch royal family) descends in the male line from his younger brother John, Count of Nassau- Dillenburg, and from the latter's fifth son, Count Ernst Casimir of Nassau- Dietz, however in the female line also from William of Orange.

Question: Who is the maternal grandfather of Johanna Of Nassau-Dillenburg?
Answer: John II of Loon