Thiébaut I of Bar, born around 1158, died Feb. 13, 1214, was Count Bar from 1190 to 1214 and the Count of Luxembourg from 1197 to 1214. He was the son of Renaud II, Count Bar, and Agnes of Champagne.
Son of Count Bar, he received first seigneuries Briey and Stenay. In the kingdom of France, it belonged to his mother by clan Thibaud de Champagne, a line facing the duchy of Lorraine at the local level and within the kingdom the center of a league opposition to the king of France Philippe Auguste.
He agrees with his brother Henry I to go on Third Crusade, and became Earl of Bar when Henry is killed at the seat of Saint-Jean-Acre.
Back in Europe, he devoted himself to increase its territorial power, through its relationships and its marriages. By his third marriage, in 1197, he acquired Luxembourg and was at the head of a huge package of territory between France and the Holy Roman Emperor. It arises in the local referee in 1202 and the Duke of Lorraine Simon II signed a treaty to ensure that their wishes regarding his succession are respected. In exchange, Thiébault receive the suzerainty County Vaudémont that will vacate the Duke of Lorraine.
He died in 1214, shortly before Bouvines. Its territory will be split into two, Barrois and its dependencies from his son and returning to Luxembourg Waleran IV of Limbourg, who married his widow.
He married in the first wedding in 1176 Laurette of Loon († 1190), daughter of Louis I, Comte de Looz and Rieneck, and Agnes of Metz, where:
* Agnes († 1226), married in 1189 at Ferry II († 1213), Duke of Lorraine
He remarried in a second marriage in 1189 with Ermesinde (1189 † 1211), daughter of Guy de Brienne, Count of Bar-sur-Seine and Elisabeth de Chacenay, where
* Henry II (1190 1239), Count of Bar
* Agnes, married to V Hugues de Chatillon († 1248), Comte de Saint-Pol and Blois
* Marguerite, married in 1221 to Henry III, Count Salm (1191 † 1228), then Henri de Dampierre († 1259)
The marriage was annulled in 1195 he married and finally third wedding in 1197 Ermesinde Ire (1186 † 1247), Countess of Luxembourg, the daughter of Henry IV, Count of Luxembourg and Namur, and Agnes of Gelderland. They were:
* Renaud, Lord of Briey, who died before 1214
* A daughter died in 1214
* Elisabeth († 1262), married to Valéran Limburg († 1242), Lord of Monschau
* Marguerite, married to Hughes III († 1243), Count of Vaudémont, then Henri de Bois, who was regent County Vaudémont.
Count Thiébaut de Bar I 
