Theodoric I, born in 965 and died between 1026 and 1027 was the count of Bar and duke of Upper Lorraine from 978 until his death. He succeeded his father, Frederick I and Beatrice, who was daughter of Hugh the Great, count of Paris, and sister to French king Hugh Capet. His mother was a regent until 987 where in 985, he joined the other Lorrainer lords, including his cousin Godfrey the Prisoner, who they tried repelling the king Lothair of France's invasion: until they hit Verdun where they were captured.