Louis I, Count of Blois

Louis I of Blois (1172 – 14 April 1205) was count of Blois from 1191 to 1205. He was the son of Theobald V and Alix of France. His maternal grandparents were Louis VII of France and his first wife Eleanor of Aquitaine.

Louis promulgated a charter in 1196 abolishing serfdom in his domains.

Leadership in the Fourth Crusade

At the Tournament at Écry-sur-Aisne on 28 November 1199, Louis and his cousin Theobald III of Champagne were the first major nobles to respond to Pope Innocent III's call for a Fourth Crusade. He left France in 1202. During the July 1203 siege of Constantinople, Louis was one of eight division commanders, the others including Boniface of Montferrat (the crusade leader), Doge Enrico Dandolo (leader of the Venetians), Baldwin of Flanders (who controlled the largest division and later became emperor), and Baldwin's brother Henry. Louis was later afflicted with a severe fever for months, and missed participating in the capture of Constantinople in 1204. He was too ill to take part in the subsequent forays of his men into Asia Minor, where he had been created Duke of Nicaea, a title he never vindicated.

He had just recuperated when he participated in the Battle of Adrianople, where he was slain by a force of Cumans led by Kaloyan of Bulgaria ("Johanitza"). Louis chased the enemy too far, exhausting his men and horses and stretching them over a broad plain, where he brought himself and the emperor Baldwin I of Constantinople into a trap.

He married Catherine, countess of Clermont-en-Beauvaisis, who bore him 3 children:

1. Raoul, who died young
2. Jeanne, who died young
3. Theobald VI of Blois (died 1218)