Eudes II of Blois

Odo II, Count of Blois
Odo II of Blois and Elias I of Maine from an engraving by Augustin François Lemaître, after a drawing by Charles Vernier () (1845)
Spouse(s)	Matilda Ermengarde
Noble family	House of Blois
Father	Odo I of Blois
Mother	Bertha of Burgundy
Born	983
Died	15 November 1037(1037-11-15) Bar-le-Duc

Odo II (French: Eudes le Champenois) (983 – 15 November 1037) was the Count of Blois, Chartres, Châteaudun, Beauvais and Tours from 1004 and Count of Troyes (as Odo IV) and Meaux (as Odo I) from 1022. He twice tried to make himself a king: first in Italy after 1024 and then in Burgundy after 1032.

Odo II was the son of Odo I of Blois and Bertha of Burgundy. He was the first to unite Blois and Champagne under one authority although his career was spent in endless feudal warfare with his neighbors and suzerains, many of whose territories he tried to annex.

About 1003/4 he married Maud of Normandy, a daughter of Richard I of Normandy. After her death in 1005, and as she had no children, Richard II of Normandy demanded a return of her dowry: half the county of Dreux. Odo refused and the two warred over the matter. Finally, King Robert II, who had married Odo's mother, imposed his arbitration on the contestants in 1007, leaving Odo in possession of the castle Dreux while Richard II kept the remainder of the lands. Odo quickly married a second wife, Ermengarde, daughter of Guilaume IV of Auvergne ().

Defeated by Fulk 'Nerra,' Count of Anjou and Herbert I of Maine at the Battle of Pontlevoy in July 1016, he quickly tried to overrun the Touraine. After the death of his cousin Stephen I in 1019/20, without heirs he seized Troyes, Meaux and all of Champagne for himself without royal approval. From there he attacked Ebles, the archbishop of Reims, and Theodoric I, the duke of Lorraine. Due to an alliance between the king and the Emperor Henry II he was forced to relinquish the county of Rheims to the archbishop.