Who created C. Auguste Dupin, the first detective character in literary fiction?

Le Chevalier C. Auguste Dupin is a fictional character created by Edgar Allan Poe. Dupin made his first appearance in Poe's "The Murders in the Rue Morgue" (1841), widely considered the first detective fiction story. He reappears in "The Mystery of Marie Rogêt" (1842) and "The Purloined Letter" (1844).

Dupin is not a professional detective and his motivations for solving mysteries change from story to story. Using what Poe termed "ratiocination", Dupin combines his considerable intellect with creative imagination, even putting himself in the mind of the criminal. His talents are strong enough that he appears able to read the mind of his companion, the unnamed narrator in all the stories.

Poe created the Dupin character before the word detective had been coined. The character laid the groundwork for fictitious detectives to come, including Sherlock Holmes.