Who is Duke Leto Atreides from Dune and what is their importance?

Duke Leto Atreides is Paul's father. He is a popular figure among feudal rulers at the time he is given the fiefdom of Dune. He never marries Lady Jessica, Paul's mother, because he believes that marriage is a matter of politics, not the heart. An assassination attempt on Paul shakes Leto to his core, and when the Mentat Thufir Hawat, his chief of security, reports finding a note that suggests Jessica is a traitor, Leto refuses to believe it. He does, however, allow her to be put under constant surveillance by Duncan Idaho. In a bloody coup d'état, Leto is drugged and killed by Dr. Wellington Yueh. Years after his death, Paul raises a desert monument over his skull, which was discovered after his cremation.