In 1125 [his father] King Stephen I England (age 31) and [his mother] Matilda Flanders (age 20) were married. She the daughter of Eustace Flanders III Count Boulogne and Mary Dunkeld Countess Boulogne 1082-1116. He the son of Stephen Blois II Count Blois and Chartres 1045-1102 and Adela Normandy Countess Blois 1067-1137 (age 58). He a grandson of King William "Conqueror" I of England. 
Around 1130 Eustace Blois IV Count Boulogne was born to King Stephen I England (age 36) and Matilda Flanders (age 25). He a great grandson of King William "Conqueror" I of England.
In 1148 Eustace Blois IV Count Boulogne (age 18) and Constance Capet Countess Boulogne and Toulose 1128-1176 (age 20) were married. She by marriage Countess Boulogne. She the daughter of Louis "Fat" VI King France and Adelaide Savoy Queen Consort France -1154. They were third cousin once removed. He a great grandson of King William "Conqueror" I of England. 
On 03 May 1152 [his mother] Matilda Flanders (age 47) died. Her son Eustace Blois IV Count Boulogne (age 22) succeeded IV Count Boulogne.
On 17 Aug 1153 King Stephen's eldest son Eustace Blois IV Count Boulogne (age 23) died at Bury St Edmunds [Map]. Probably from food poisoning, possibly murdered for having sacked the Abbey. His brother [his brother] William Blois I Count Boulogne 1137-1159 (age 16) succeeded I Count Boulogne.
After 17 Aug 1153 Eustace Blois IV Count Boulogne (age 23) was buried at Faversham Abbey, Kent [Map].
On 16 Aug 1176 [his former wife] Constance Capet Countess Boulogne and Toulose 1128-1176 (age 48) died.
and Constance Capet Countess Boulogne and Toulose 1128-1176 were married. She by marriage Countess Toulose. She the daughter of Louis "Fat" VI King France and Adelaide Savoy Queen Consort France -1154. He the son of .
Peter Courtenay and Elizabeth Courtenay were married. He the son of Louis "Fat" VI King France and Adelaide Savoy Queen Consort France -1154.
Kings Wessex: Great x 3 Grand Son of King Edmund "Ironside" I of England
Kings England: Great Grand Son of King William "Conqueror" I of England
Kings Scotland: Great Grand Son of Malcolm III King Scotland
Kings Franks: Great x 8 Grand Son of Louis "Pious" King Aquitaine I King Franks
Kings France: Great x 3 Grand Son of Robert "Pious" II King France
Great x 4 Grandfather: Theobald "Trickster" Blois I Count Blois 913-975
Great x 3 Grandfather: Odo Blois I Count Blois 950-996
Great x 4 Grandmother: Luitgarde Vermandois Duchess Normandy 915-978
Great x 2 Grandfather: Odo Blois II Count Blois 983-1037
Great x 4 Grandfather: Conrad I King Burgundy 925-993
Great x 3 Grandmother: Bertha Welf Queen Consort France 964-1010
Great x 4 Grandmother: Mathilde Carolingian Queen Consort Burgundy 943-992
Great x 1 Grandfather: Theobald Blois III Count Blois
Great x 3 Grandfather: William IV Auvergne
Great x 2 Grandmother: Ermengarde Auvergne Countess Blois 970-1040
GrandFather: Stephen Blois II Count Blois and Chartres 1045-1102
Great x 4 Grandfather: Conan "Crooked" Penthièvre III Duke Brittany -992
Great x 3 Grandmother: Unamed Penthièvre Countess Maine
Great x 4 Grandmother: Ermengarde Gerberga Ingelger Duchess Brittany 956-1024
Father: King Stephen I England Grand Son of King William "Conqueror" I of England
Great x 4 Grandfather: Richard "Fearless" Normandy I Duke Normandy 932-996
Great x 3 Grandfather: Richard "Good" Normandy II Duke Normandy
Great x 2 Grandfather: Robert "Magnificent" Normandy I Duke Normandy
Great x 4 Grandfather: Conan "Crooked" Penthièvre III Duke Brittany -992
Great x 3 Grandmother: Judith Penthièvre Duchess Normandy 982-1017
Great x 4 Grandmother: Ermengarde Gerberga Ingelger Duchess Brittany 956-1024
Great x 1 Grandfather: King William "Conqueror" I of England -2 x Great Grand Son of King William "Conqueror" I of England
Great x 3 Grandfather: Father of Beatrix and Herleva
Great x 2 Grandmother: Herleva Falaise
GrandMother: Adela Normandy Countess Blois 1067-1137 Daughter of King William "Conqueror" I of England
Great x 4 Grandfather: Arnulf II Count Flanders 960-987
Great x 3 Grandfather: Baldwin "Bearded" IV Count Flanders 980-1035
Great x 4 Grandmother: Rozala of Italy 950-1003
Great x 2 Grandfather: Baldwin "The Good" V Count Flanders
Great x 4 Grandfather: Frederick Luxemburg Ardennes
Great x 3 Grandmother: Ogive Luxemburg Countess Flanders -1036
Great x 4 Grandmother: Ermentrude Gleiburg
Great x 1 Grandmother: Matilda Flanders Queen Consort England
Great x 4 Grandfather: Hugh I King France
Great x 3 Grandfather: Robert "Pious" II King France
Great x 4 Grandmother: Adelaide Poitiers Queen Consort France 945-1004
Great x 2 Grandmother: Adela Capet Duchess Normandy 1009-1079
Great x 4 Grandfather: William "Liberator" Arles 1st Count Provence 1st Count Arles
Great x 3 Grandmother: Constance Arles Queen Consort France 986-1034
Great x 4 Grandmother: Adelaide Blanche Ingelger Queen Consort West Francia 940-1026
Eustace Blois IV Count Boulogne 1130-1153 Great Grand Son of King William "Conqueror" I of England
Great x 4 Grandfather: Arnulf Flanders III Count Boulogne -990
Great x 3 Grandfather: Baldwin Flanders II Count Boulogne -1027
Great x 2 Grandfather: Eustace Flanders I Count Boulogne -1049
Great x 4 Grandfather: Arnulf Gerulfing Count Holland 950-993
Great x 3 Grandmother: Adelina Gerulfing Countess Boulogne and Ponthieu
Great x 4 Grandmother: Luitgarde Luxemburg Countess Holland
Great x 1 Grandfather: Eustace Flanders II Count Boulogne
Great x 4 Grandfather: Reginar Reginar III Count Hainault 920-973
Great x 3 Grandfather: Lambert "Bearded" Reginar I Count Louvain 950-1015
Great x 2 Grandmother: Matilda Reginar Countess Boulogne
Great x 4 Grandfather: Charles Carolingian Duke Lower Lorraine 953-991
Great x 3 Grandmother: Gerberga Carolingian Duchess Lower Lorraine 975-1018
GrandFather: Eustace Flanders III Count Boulogne
Great x 4 Grandfather: Godfrey "The Prisoner" Ardennes I Count Verdun -1002
Great x 3 Grandfather: Gothelo Ardennes Duke Lower Lorraine Duke Upper Lorraine -1044
Great x 4 Grandmother: Matilda Billung Countess Flanders 940-1008
Great x 2 Grandfather: Godfrey "Bearded" Ardennes III Duke Lower Lorraine 997-1069
Great x 1 Grandmother: Ida Ardennes Countess Boulogne
Mother: Matilda Flanders
Great x 2 Grandfather: Duncan "The Sick" I King Scotland 1001-1040
Great x 1 Grandfather: Malcolm III King Scotland
GrandMother: Mary Dunkeld Countess Boulogne 1082-1116
Great x 4 Grandfather: King Æthelred "Unready" II of England
Great x 3 Grandfather: King Edmund "Ironside" I of England
Great x 2 Grandfather: Edward "The Exile" Wessex
Great x 3 Grandmother: Ealdgyth Unknown
Great x 1 Grandmother: Margaret Wessex Queen Consort Scotland
Great x 2 Grandmother: Agatha