duke of Lotharingia (Lorraine) from 944 to 953 and ancestor of the Salian dynasty of German kings.

Conrad belonged to a family of Franconian counts with rich lands in the country around Speyer and Worms. After helping King (later Emperor) Otto I suppress a rebellion of his vassals (937–939), he was given the duchy of Lotharingia (944) and Otto's daughter Liudgard in marriage. Later he fell out with the king and joined Otto's son Liudolf of Swabia in a rebellion (953–954). Forced to submit, Conrad lost his duchy but not his lands in Franconia or his vassals. Later reunited with the king, he fought and was killed in the Battle of Lechfeld, when the largest Hungarian army to invade German lands was destroyed. His services seem to have been decisive in securing this victory for Otto.

duke of Lower Lorraine (1076–89), eldest son of the emperor Henry IV, who had him crowned king of the Germans in 1087 in an attempt to confirm the imperial succession in the Salian line. During Henry's struggles with the papacy, however, Conrad turned against his father, joined the papal party, and was crowned king of Italy (1093). In return for fealty, Pope Urban II promised him the imperial crown (1095). Conrad never succeeded in developing a sizable following, was deposed by his father in favour of his brother Henry V (1099), and died two years later, discredited as a rebel son.