Duke Leto Atreides I (10,140-10,191 A.G.) was the reigning head of House Atreides. He was also known as the Red Duke.
Leto was the son of Duke Paulus Atreides and Lady Helena Atreides. Paulus was reigning Duke of House Atreides, their house having ruled planet Caladan for 26 generations. The Atreides related to the Imperial House Corrino and had carried a deep feud with House Harkonnen for generations.
His father, Duke Paulus Atreides, arranged for him to spend a portion of his adolescence on planet Ix in the care of House Vernius and its then-Earl, Dominic Vernius. There, Leto became fast friends with the Earl's son, Prince Rhombur Vernius and his daughter, Kailea Vernius. They returned to Caladan after the uprising of Ix's working class of mentally limited subhumans and subsequent Tleilaxu invasion.
His father had engaged in the sport of bullfighting, both for the sport and for the spectacle - He would play every bull for all it was worth, and the people of Caladan loved him for it. He was killed by his treacherous Richese wife through a Salusan bull drugged to extraordinary levels of rage, strength and endurance by the stableman, Yresk, a loyalist to House Richese, from which Lady Helena originated. Leto realized what she had done immediately, and banished her to live in a remote location with the Sisters in Isolation rather than execute her, as public knowledge of what she had done would have a large impact on House Atreides.
Leto kept a portrait of his father and the head of the beast as a grisly sort of reminder to the event.
Leto eventually took Kailea as his concubine, and they had a son named Victor. However, Leto refused to take Kailea as his wife or name Victor as his heir, preferring to keep a political marriage a possibility. Leto and Kailea eventually grew apart, and after the arrival of a second, Bene Gesserit concubine whom Leto found himself freshly attracted to, and in love with, she attempted to take matters into her own hands by attempting to kill Leto. Kailea's plot failed, but her brother Rhombur was severely injured in the process, while her son Victor was killed.
Leto eventually took the Bene Gesserit acolyte, Jessica, as his bound concubine. They never married in order to maintain, as always, the possibility of an alliance with another Great House - although this would ultimately never occur. Unknown to him was that Jessica was the illegitimate daughter of his rival Vladimir Harkonnen. Leto and Jessica were utterly devoted to each other in every way - any marriage on Leto's part would have been purely political, and meaningless to him. In year 10,176 Jessica gave birth to Paul Atreides, their first son.
Leto was known in some Imperial circles, and especially by the Emperor, as "the Red Duke" and gained fame as an effective politician, a fair and just statesman, and a capable leader of his small army. He recruited skilled individuals, including Thufir Hawat, Gurney Halleck and Duncan Idaho to serve under him and train his soldiers. Jessica and Hawat also served as his two main advisors. Leto was greatly disliked by the Padishah Emperor Shaddam Corrino IV due to an incident in his youth in which Leto had made a bluffing attempt to blackmail the Emperor into intervening on his behalf in court, where he had submitted to a Trial by Forfeiture to prove that he had not fired on another ship inside a Heighliner in foldspace. He had, in fact, been framed for this by longtime rival Vladimir Harkonnen.
In year 10, 191 Leto's two greatest enemies conspired against him. Vladimir was forced by the emperor to surrender Arrakis to Leto, requiring Leto to leave Caladan.
His term as Duke of Arrakis would prove short, as he was betrayed by Dr. Wellington Yueh, his family physician and surrendered alive to the Baron Harkonnen. Yueh, in revenge against the Baron for killing his wife, provided Leto with a false tooth filled with poison gas.
It was designed to kill those nearby when Leto bit down on the tooth and exhaled, in the hope that he would manage to kill the Baron. Unfortunately for both Yueh's plans and Leto, he only managed to kill the twisted mentat Piter De Vries. Leto was 51 years old.
Leto was survived by Paul, and Jessica, who was pregnant with Leto's daughter, Alia, at the time of his death.
In the films
In David Lynch's 1984 film version, Leto was played by Jurgen Prochnow. In the Sci-Fi Channel miniseries, William Hurt played the role.