Count of Blois, Chartres and Tourain was slain in battle by Godfrey Martel Count of Anjou. Europaische Stammtafeln says he died in 1089.

3Theobald III of Blois (French: Thibaut) (1012–1089) was count of Blois, Meaux and Troyes. He was son of Odo II of Blois and Ermengarde of Auvergne.
Theobald inherited amongst others the counties of Blois, Tours, Chartres. Chateaudun and Sancerre, and also in Champagne: Château-Thierry, Provins and St. Florentin. His brother Stephen inherited the counties of Meaux, Troyes and Vitry-le-François.
Theobald conspired against the king of France Henry I, was beaten in 1044 and had to give up the county of Tours to regain his freedom. From then on the centre of power for the House of Blois moved to Champagne. Theobald found ways to become close to the royal court again and gain influence. He got the title of Count Palatine, which his father had used before. He used this influence to get control over his brother's possessions in Champagne that were inherited by his minor nephew Odo of Troyes. Odo later joined the army of William the Conqueror, participated in the battle of Hastings, married a sister of William and became count of Aumale and Holderness.
Theobald had a position of considerable power, that increased when he married the daughter of Raoul de Valois. From 1074 onward, he left his son Henry in control of Blois, Chateaudun and Chartres.

Married to von Maine, Garsende

Child 1: , Stephen II Henry of Blois, Count of Blois, b. ABT 1045
Child 2: , Odo (Eudes) III of Blois, Count of Blois
Child 3: , Hugo (Hugh) I of Blois, Count of Blois
Child 4: , Philipp of Chalons, Baron von Chalons