Question: Who is the maternal grandfather of Eustace Iii, Count Of Boulogne?

Knowledge 1: Eustace III, Count of Boulogne
Eustace III (died c. 1125) was the count of Boulogne from 1087, succeeding his father Count Eustace II.His mother was Ida of Lorraine.In 1088, Eustace supported the rebellion against William II of England in favour of Robert Curthose.Eustace participated in the First Crusade of 1096 along with his brothers Godfrey of Bouillon (duke of Lower Lotharingia) and Baldwin of Boulogne.It is unclear whether he travelled eastward with his brother Godfrey's or Robert Curthose's army.His contingent included Hugh II of Saint-Pol and his son Engelrand, Eustace I Granarius, lord of Sidon and Caesarea, Fulk of Guînes, and Hugh of Robecq (Rebecques), lord of Hebron.Throughout the crusade Eustace assisted Godfrey.Eustace was present at the Siege of Nicaea (May–June 1097), helped rescue Bohemund of Taranto's beleaguered troops at the Battle of Dorylaeum (July 1, 1097), defeated an enemy ambush during the Siege of Antioch and was one of the commanders during the capture of Antioch on June 3, 1098.Eustace was a member of the council held at Ruj on January 4, 1099, mediating in the conflict over the control of Antioch between Bohemund of Taranto and Raymond IV of Toulouse.Early December 1098 Eustace joined Raymond's attack on Maarrat al-Nu'man and an attack on Nablus in July 1099.He gained notoriety for his actions during the Siege of Jerusalem fighting relentlessly from a siege tower along with his brother Godfrey and the warriors they commanded.They were among the first to breach Jerusalem's city walls and participated in the ensuing massacre.Finally Eustace commanded a division of the crusader army during the Battle of Ascalon.While his brothers stayed in the Holy Land, Eustace returned to administer his domains.To commemorate Eustace's crusading adventures the mint at Boulogne struck silver coins with a lion above the walls of Jerusalem stamped on the obverse.Eustace married Mary, daughter of King Malcolm III of Scotland and Saint Margaret of Scotland.Eustace and Mary had one daughter:When his youngest brother king Baldwin I of Jerusalem died in 1118, the elderly Eustace was offered the throne.Eustace was at first uninterested, but was convinced to accept it; he travelled all the way to Apulia before learning that a distant relative, Baldwin of Bourcq, had been crowned in the meantime.Eustace returned to Boulogne and died about 1125.On his death the county of Boulogne was inherited by his daughter, Matilda, and her husband Stephen de Blois, count of Mortain, afterwards king of England.Eustace founded the Cluniac house of Rumilly and was patron of the Knights Templar. [SEP] Knowledge 2: 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 wasGothelo I, Duke of Lorraine and Ida's brother was Godfrey IV, Duke of Lower Lorraine.
Knowledge 1: 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 wasGothelo I, Duke of Lorraine and Ida's brother was Godfrey IV, Duke of Lower Lorraine. [SEP] Knowledge 2: Eustace I, Count of Boulogne
Eustace I, Count of Boulogne, was a nobleman and founder of the Boulogne branch of the House of Flanders.He held the county of Boulogne from 1024 until his death in 1049.
Knowledge 1: Eustace III, Count of Boulogne
Eustace III (died c. 1125) was the count of Boulogne from 1087, succeeding his father Count Eustace II.His mother was Ida of Lorraine.In 1088, Eustace supported the rebellion against William II of England in favour of Robert Curthose.Eustace participated in the First Crusade of 1096 along with his brothers Godfrey of Bouillon (duke of Lower Lotharingia) and Baldwin of Boulogne.It is unclear whether he travelled eastward with his brother Godfrey's or Robert Curthose's army.His contingent included Hugh II of Saint-Pol and his son Engelrand, Eustace I Granarius, lord of Sidon and Caesarea, Fulk of Guînes, and Hugh of Robecq (Rebecques), lord of Hebron.Throughout the crusade Eustace assisted Godfrey.Eustace was present at the Siege of Nicaea (May–June 1097), helped rescue Bohemund of Taranto's beleaguered troops at the Battle of Dorylaeum (July 1, 1097), defeated an enemy ambush during the Siege of Antioch and was one of the commanders during the capture of Antioch on June 3, 1098.Eustace was a member of the council held at Ruj on January 4, 1099, mediating in the conflict over the control of Antioch between Bohemund of Taranto and Raymond IV of Toulouse.Early December 1098 Eustace joined Raymond's attack on Maarrat al-Nu'man and an attack on Nablus in July 1099.He gained notoriety for his actions during the Siege of Jerusalem fighting relentlessly from a siege tower along with his brother Godfrey and the warriors they commanded.They were among the first to breach Jerusalem's city walls and participated in the ensuing massacre.Finally Eustace commanded a division of the crusader army during the Battle of Ascalon.While his brothers stayed in the Holy Land, Eustace returned to administer his domains.To commemorate Eustace's crusading adventures the mint at Boulogne struck silver coins with a lion above the walls of Jerusalem stamped on the obverse.Eustace married Mary, daughter of King Malcolm III of Scotland and Saint Margaret of Scotland.Eustace and Mary had one daughter:When his youngest brother king Baldwin I of Jerusalem died in 1118, the elderly Eustace was offered the throne.Eustace was at first uninterested, but was convinced to accept it; he travelled all the way to Apulia before learning that a distant relative, Baldwin of Bourcq, had been crowned in the meantime.Eustace returned to Boulogne and died about 1125.On his death the county of Boulogne was inherited by his daughter, Matilda, and her husband Stephen de Blois, count of Mortain, afterwards king of England.Eustace founded the Cluniac house of Rumilly and was patron of the Knights Templar. [SEP] Knowledge 2: Eustace I, Count of Boulogne
Eustace I, Count of Boulogne, was a nobleman and founder of the Boulogne branch of the House of Flanders.He held the county of Boulogne from 1024 until his death in 1049.

Answer: Godfrey III, Duke of Lower Lorraine