De Lassus, Carlos Dehault, soldier and lieutenant governor of Upper Louisiana, was a native of Lille, France, where he was born in 1764, but at the age of 18 years entered the Spanish army as a member of the royal guards commanded by the king himself. For his distinguished bravery in the assault on Fort Elmo in 1793 he was made lieutenant-colonel, having previously won his commission as captain of grenadiers. In the French revolution of 1793 his father was driven from his native land and found refuge in New Orleans. Owing to this fact, when Carlos was assigned to the command of a battalion of the king's body-guard in 1874, he asked to be transferred to New Orleans that he might have the privilege of being near his father in a foreign land. His request was granted, and soon after his arrival in this country he was made lieutenant-colonel of the Louisiana regiment. For about three years he was commandant at New Madrid, where he distinguished himself by the capture of five Creek Indians who were causing trouble and the execution of the leader. On Aug. 29, 1799, he was appointed lieutenant-governor of Upper Louisiana, which included the territory now comprising the State of Kansas, and remained in that office until March 9, 1804, when, pursuant to orders from the Spanish authorities, he delivered the province to Maj. Amos Stoddard, the representative of the United States government. Upon that date De Lassus issued the following proclamation to the people of the province:

"Inhabitants of Upper Louisiana; By the King's command, I am about to deliver up this post and its dependencies. The flag under which you have been protected for a period of nearly 36 years is about to be withdrawn. From this moment you are released from the oath of fidelity you took to support it. The fidelity and courage with which you have guarded and defended it will never he forgotten; and in my character of representative I entertain the most sincere wishes for your perfect prosperity."

De Lassus remained at St. Louis until the following autumn, when he was ordered with his regiment to Florida. For a time he was stationed at Pensacola, and later was appointed governor of West Florida, with headquarters at Baton Rouge. Here he was captured by local militia in the uprising of 1810. Shortly after this he resigned his commission and became a private citizen of New Orleans, where he died on May 1, 1842.