Adelolf, Count of Boulogne
Adelolf, Count of Boulogne( † 933), was a younger brother of Arnulf I, Count of Flanders and was given the County of Boulogne by his father.
He was a son of Baldwin II, Count of Flanders, and of Ælfthryth, daughter of Alfred the Great.
He was probably named for his maternal great- grandfather, King Æthelwulf of Wessex.
Baldwin II's extensive lands and many offices in what is now the north of modern France and the west of Belgium were divided among his sons on his death in 918.
The elder, Arnulf, became Count of Flanders while Adelolf succeeded his father as count of Saint- Pol, Count of Boulogne and of Thérouanne.
He was also the lay abbot of the Abbey of Saint Bertinus( Saint- Bertin) at Saint- Omer.
In 926 Adelolf was sent as an ambassador to his maternal first cousin King Æthelstan of England by Count Hugh the Great, effective ruler of northern France under Rudolph, Duke of Burgundy, who had been elected king of France in 923.
Adelolf was to seek the English king's agreement to a marriage between Hugh and another of Æthelstan's sisters.
Among the lavish gifts sent to Æthelstan, an avid collector of relics, were said to be the sword of the Roman Emperor Constantine the Great and the Holy Lance.
The embassy was a success and Hugh was married to Æthelstan's half- sister Eadhild.
In 933, Æthelstan's half- brother Edwin was drowned and his body cast ashore.
Adelolf received the body of his kinsman with honour and took it to the Abbey of Saint Bertin for burial.
Adelolf was the father of Arnulf II, Count of Boulogne( † 971), and of an illegitimate son named Baldwin( died 973) who was guardian of Arnulf II, Count of Flanders.
Adelolf died in 933.
He was buried at Saint- Bertin.
Baldwin II, Count of Hainaut
Baldwin II of Mons( 1056–1098?) was count of Hainaut from 1071 to his death.
He was the younger son of Baldwin VI, Count of Flanders and Richilde, Countess of Mons and Hainaut.
Baldwin III, Count of Hainaut
Baldwin III( 1088–1120) was count of Hainaut from 1098 to his death.
He was son of Baldwin II, Count of Hainaut, and Ida of Louvain.
Adelina of Holland
Adelina of Holland was possibly a daughter of Arnulf, Count of Holland, and Lutgardis of Luxemburg.
She married firstly Baldwin II, Count of Boulogne( with whom she had Eustace I of Boulogne), and secondly Enguerrand I of Ponthieu.
Arnulf III, Count of Boulogne
Arnulf III of Boulogne († 990) was a son of Arnulf II, Count of Boulogne.
He succeeded his father as count of Boulogne from 972 to 990.
On his death his lands were divided between his three sons:
Marie of Brienne
Marie of Brienne( c. 1224–1275) was Latin Empress as the wife of Baldwin II of Courtenay.
She served as regent during the absence of Baldwin II twice: in 1237 – 1239, and in 1243 – 1257.
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.
Baldwin II, Count of Boulogne
Baldwin II of Boulogne  was a son of Arnulf III, Count of Boulogne, whom he succeeded as count of Boulogne.
Arnulf II, Count of Boulogne
Arnulf II of Boulogne( † 972) was a son of Count Adalolf.
He succeeded as Count of Boulogne in 964 after the death of his uncle Arnulf I, and held it until his own death.
He was the father of Arnulf III, Count of Boulogne.
He is the ancestor of Ruler of Jerusalem Godfrey of Bouillon.
Baldwin II, Count of Guînes
Sir Baldwin II, Count of Guînes( died 2 January 1205), was a French nobleman.

Question: Who is Baldwin Ii, Count Of Boulogne's paternal grandfather?