Ernest Constantine, Landgrave of Hesse-Philippsthal
Ernest Constantine, Landgrave of Hesse-Philippsthal (8 August 1771 in Philippsthal – 25 December 1849 in Meiningen) was a member of the House of Hesse and Landgrave of Hesse-Philippsthal from 1816 until his death.
Margravine Hedwig Sophie of Brandenburg
Hedwig Sophia of Brandenburg( 14 July 1623, Berlin- 26 June 1683, Schmalkalden) was Landgravine consort of Hesse- Kassel by marriage to William VI, Landgrave of Hesse- Kassel, and regent from 1663 until 1677 during the minority of her sons, William VII, Landgrave of Hesse- Kassel and Charles I, Landgrave of Hesse- Kassel.
Hermann II, Landgrave of Hesse
Hermann II of Hesse( 1341 – 24 May 1413) was Landgrave of Hesse from 1376 to 1413.
Hermann II, called" the Scholar", was born in 1345 in Burg Grebenstein( Grebenstein castle), the son of Louis the Junker.
Louis the Junker was a son of Otto I, Landgrave of Hesse.
Hermann studied in Paris and in Prague.
After the death of Otto, the son and heir apparent of Henry II, the latter appointed his nephew Hermann as co-ruler and heir in 1367.
Hermann was married twice.
The first marriage on 3 February 1377 was to Johanna, countess of Nassau- Weilburg[ 1383] but produced no children.
The second was on 15 October 1383 to Margaret of Hohenzollern- Nuremberg[ 1406], daughter of Frederick V, Burgrave of Nuremberg.
They had the following children:
Henry I, Landgrave of Hesse
Henry I of Hesse "the Child"
(German: "Heinrich das Kind") (24 June 1244 – 21 December 1308) was the first Landgrave of Hesse.
He was the son of Henry II, Duke of Brabant and Sophie of Thuringia.
Moritz, Landgrave of Hesse
Moritz, Prince and Landgrave of Hesse(" Moritz Friedrich Karl Emanuel Humbert" 6 August 1926 – 23 May 2013) was the son of Prince Philip, Landgrave of Hesse, and the head of the House of Brabant and the German House of Hesse.
Gustav, Landgrave of Hesse-Homburg
Gustav, Landgrave of Hesse- Homburg( 17 February 1781 – 8 September 1848) was landgrave of the German state of Hesse- Homburg from 1846 to 1848.
Charles I, Landgrave of Hesse-Philippsthal
Charles I, Landgrave of Hesse- Philippsthal( 23 September 1682 – 8 May 1770) was a member of the House of Hesse and Landgrave of Hesse- Philippsthal from 1721 until his death.
Otto I, Landgrave of Hesse
Otto I of Hesse (c. 1272 – 17 January 1328) was Landgrave of Hesse from 1308 until his death.
Otto was born in Marburg, a son of Henry I, Landgrave of Hesse and his first wife Adelheid of Brunswick-Lunenburg.
Following the death of his father in 1308, he inherited Upper Hesse, the "Land on the Lahn", which included Marburg, Giessen, Grünberg and Alsfeld.
After his half-brother John died in 1311, he also became landgrave of Lower Hesse.
This included the area below the Fulda, Eder, Schwalm, Werra, and the upper reaches of the Weser, with the residence of Kassel, as well as the towns of Homberg (Efze), Melsungen, and Rotenburg an der Fulda.
After Otto inherited the whole Landgraviate, he resided alternately in Kassel and Marburg.
Otto had a long conflict with the Archbishop of Mainz, Matthias von Bucheck.
In 1324 Mainz won the battle in the Lahnberg with help from troops from Amöneburg.
In 1327, Mainz adopted Giessen with the help of troops from the Electorate of Trier, but the citizens of the town quickly enabled Otto to regain control.
Only after Otto's victory at Wetzlar and with the mediation of King John of Luxembourg in 1328 was conciliation made possible.
Otto died on 17 January 1328 in Kassel, and was buried in the Ahnaberg monastery.
Philip, Landgrave of Hesse-Philippsthal
Philip of Hesse- Philippsthal( 14 December 1655 – 18 June 1721) was the son of William VI, Landgrave of Hesse- Kassel and Hedwig Sophia of Brandenburg.
He was the first landgrave of Hesse- Philippsthal from 1663 to 1721 and the founder of the fifth branch of the house of Hesse.
Henry II, Landgrave of Hesse
Henry II of Hesse( German:" Heinrich"),( c. 1299 – 3 June 1376) called" the Iron" was Landgrave of Hesse from 1328 – 1376.
Henry was the son of Otto I, Landgrave of Hesse and Adelheid of Ravensburg.
With his wife Elisabeth of Thuringia, daughter of Frederick I, Margrave of Meissen, he had five children: When Henry's son Otto died in 1366, his nephew Hermann was named co-regent.
This caused fighting to break out with Otto of Brunswick.
To defray the costs of the conflict with Brunswick, Henry levied a tax on all imported goods.

Question: Who is the paternal grandfather of Otto I, Landgrave Of Hesse?
Answer: Henry II