Eleanor was originally fourth in line to the inheritance of the county, being her father's youngest child.
However, her oldest brother Hugh II abdicated to become a monk in 1160, her second brother Ralph II died of leprosy in 1176, leaving no children and Eleanor's sister Elisabeth died in 1183.
Her marriage to Philip I, Count of Flanders, had produced no children; therefore, Eleanor could then rightfully inherit the County of Vermandois.

Upon the death of Elisabeth, her widower Count Philip refused to pass over control of Vermandois to Eleanor; she then appealed to Philip II of France for support.
Under the Treaty of Amiens on 20 March 1186, Eleanor retained Valois and part of Vermandois, calling herself at that point Countess of Valois, then upon the death of Philip in 1192, she inherited the rest of Vermandois on the condition that King Philip was able to annex Vermandois into the royal domain if Eleanor died without children.

From that point onward, Eleanor reigned solely over Vermandois.
Eleanor was remembered as a witty yet pious woman.
She founded the Abbey of Parc-aux-Dames in Auger-Saint-Vincent, she loved poetry and gave the minister Renaud impetus to the Constitution of the Roman de Sainte-Geneviève.
She also donated property to Notre-Dame by charter dated 1189.

Eleanor died childless in 1213 at the age of sixty after a 21-year rule over Vermandois, and she was buried in the Abbey of Longpont (today she is buried in Aisne).
Upon Eleanor's death, King Philip took over control of all of Eleanor's property.
Eleanor was originally fourth in line to the inheritance of the county, being her father's youngest child. However, her oldest brother Hugh II abdicated to become a monk in 1160, her second brother Ralph II died of leprosy in 1176, leaving no children and Eleanor's sister Elisabeth died in 1183. Her marriage to Philip I, Count of Flanders, had produced no children; therefore, Eleanor could then rightfully inherit the County of Vermandois.
Upon the death of Elisabeth, her widower Count Philip refused to pass over control of Vermandois to Eleanor; she then appealed to Philip II of France for support. Under the Treaty of Amiens on 20 March 1186, Eleanor retained Valois and part of Vermandois, calling herself at that point Countess of Valois, then upon the death of Philip in 1192, she inherited the rest of Vermandois on the condition that King Philip was able to annex Vermandois into the royal domain if Eleanor died without children.
From that point onward, Eleanor reigned solely over Vermandois. Eleanor was remembered as a witty yet pious woman. She founded the Abbey of Parc-aux-Dames in Auger-Saint-Vincent, she loved poetry and gave the minister Renaud impetus to the Constitution of the Roman de Sainte-Geneviève. She also donated property to Notre-Dame by charter dated 1189. 
Eleanor died childless in 1213 at the age of sixty after a 21-year rule over Vermandois, and she was buried in the Abbey of Longpont (today she is buried in Aisne). Upon Eleanor's death, King Philip took over control of all of Eleanor's property.
Eleanor, Countess of Vermandois