Baldwin V, Count of Flanders
Baldwin V of Flanders( c. 1012 – 1 September 1067) was Count of Flanders from 1035 until his death.
He was the son of Baldwin IV, Count of Flanders, who died in 1035.
Isabella of Ibelin (died 1315)
Isabella of Ibelin( died 1315) was the daughter of Baldwin of Ibelin( d. 1313), lord of Korakou, and of Marguerite de Giblet.
Baldwin I of Jerusalem
Baldwin I , also known as Baldwin of Boulogne (1060s – 2April 1118), was the first count of Edessa from 1098 to 1100, and the first king of Jerusalem from 1100 to his death.
Being the youngest son of Eustace II, Count of Boulogne, and Ida of Lorraine, he was destined for a church career, but he abandoned it and married a Norman noblewoman, Godehilde of Tosny.
He received the County of Verdun in 1096, but he soon joined the crusader army of his brother Godfrey of Bouillon and became one of the most successful commanders of the First Crusade.
While the main crusader army was marching across Asia Minor in 1097, Baldwin and the Norman Tancred launched a separate expedition against Cilicia.
Tancred tried to capture Tarsus in September, but Baldwin forced him to leave it, which gave rise to an enduring conflict between them.
Baldwin seized important fortresses in the lands to the west of the Euphrates with the assistance of local Armenians.
Thoros of Edessa invited him to come to Edessa to fight against the Seljuqs.
Taking advantage of a riot against Thoros, Baldwin seized the town and established the first crusader state on 10March 1098.
To strengthen his rule, the widowed Baldwin married an Armenian ruler's daughter (who is now known as Arda).
He supplied the main crusader army with food during the siege of Antioch.
He defended Edessa against Kerbogha, the governor of Mosul, for three weeks, preventing him from reaching Antioch before the crusaders captured it.
Godfrey of Bouillon, whom the crusaders had elected their first ruler in Jerusalem, died in 1100.
Daimbert, the Latin patriarch, and Tancred offered Jerusalem to Tancred's uncle, Bohemond I of Antioch.
Godfrey's retainers took possession of the town and urged Baldwin to claim Godfrey's inheritance.
Since a Muslim ruler captured Bohemond, Baldwin marched to Jerusalem meeting little resistance.
The Patriarch crowned him king in Bethlehem on 25December.
He captured Arsuf and Caesarea in 1101, Acre in 1104, Beirut in 1110, and Sidon in 1111, with the assistance of Genoese and Venetian fleets and of several smaller crusader groups, but all his attempts to capture Ascalon and Tyre failed.
After his victory at the third battle of Ramla in 1105, the Egyptians launched no further major campaigns against the Kingdom of Jerusalem.
Baldwin helped Bertrand, Count of Toulouse, to capture Tripoli in 1109.
Being the only crowned monarch in the Latin East, Baldwin claimed suzerainty over other crusader rulers.
Baldwin II of Edessa and Bertrand swore fealty to him.
Tancred, who ruled the Principality of Antioch, also obeyed his summons.
He supported Baldwin II and Tancred against Kerbogha's successor, Mawdud, who launched a series of campaigns against Edessa and Antioch in the early 1110s.
He erected fortresses in Oultrejordainthe territory to the east of the Jordan Riverto control the caravan routes between Syria and Egypt.
He died during a campaign against Egypt.
Eschiva of Ibelin (died 1196)
Eschiva of Ibelin( 1160 – 1196) was a queen consort of Cyprus.
She was the daughter of Baldwin of Ibelin( died 1187), lord of Ramla, and of Richilde de Bethsan, and a member of the influential Ibelin family.
She married Aimery of Cyprus( 1145 – 1205), constable of the kingdom of Jerusalem, later king of Cyprus( 1194 – 1205) and of Jerusalem( 1197 – 1205).
Their children were:
Arda of Armenia
Arda( died after 1116) was the queen of the Jerusalem as the 2nd spouse of King Baldwin I of Jerusalem.
She was the first Queen consort of the Kingdom of Jerusalem, as Baldwin's brother and predecessor Godfrey of Bouillon was unmarried.
Sibylla, Queen of Jerusalem
Sibylla (French: "Sibylle", c. 1160–1190) was the Countess of Jaffa and Ascalon from 1176 and Queen of Jerusalem from 1186 to 1190.
She was the eldest daughter of Amalric I of Jerusalem and Agnes of Courtenay, sister of Baldwin IV and half-sister of Isabella I of Jerusalem, and mother of Baldwin V of Jerusalem.
Her grandmother Melisende had provided an example of successful rule by a queen regnant earlier in the century.
Ida of Lorraine
Ida of Lorraine (also referred to as Blessed Ida of Boulogne)
(c. 1040 – 13 April 1113) was a saint and noblewoman.
She was the daughter of Godfrey III, Duke of Lower Lorraine and his wife Doda.
Ida's grandfather was
Gothelo I, Duke of Lorraine and Ida's brother was Godfrey IV, Duke of Lower Lorraine.
Kaya Alp
Kaya Alp was, according to Ottoman tradition, the son of Kızıl Buğa and the father of Suleyman Shah, who was, in turn, the grandfather of Ertuğrul, and the great grandfather of the Ottoman Empire founder, Osman I.
Benedict I of Jerusalem
Patriarch Benedict of Jerusalem, also Benediktos I of Jerusalem, born Vasileios Papadopoulos (1892 – December 10, 1980) was the Patriarch of Jerusalem of the Greek Orthodox Church of Jerusalem from 1957 to 1980.
Simon, Constable of Jerusalem
Simon was the first known constable of Jerusalem.
He is cited in two royal charters, the first in 1108 and the second in 1115 as" Symon ducis filius".
He may be identified with the Simontos, mentioned by Anna Comnena as an envoy of Baldwin I of Jerusalem to Tripoli in order to receive Greek ambassadors in 1108.
She calls him a cousin of the king.
Together these imply that he was likely a son of Henry, Duke of Lower Lorraine, a great- grandson of Eustace I of Boulogne by his maternal grandmother.

Question: Who is the maternal grandfather of Baldwin I Of Jerusalem?
Answer: Godfrey III, Duke of Lower Lorraine