Two of the most powerful, Lambert and Reginald, were brothers.

They made common cause against the new duke; and after a desperate struggle, which did not cease till the year 985, they gained a species of imperfect independence--Lambert becoming the root from which sprang the counts of Louvain, and Reginald that of the counts of Hainault.
The emperor Othon II., who upheld the authority of his lieutenant, Godfrey, became convinced that the imperial power was too weak to resist singly the opposition of the nobles of the country.
He had therefore transferred, about the year 980, the title of duke to a young prince of the royal house of France; and we thus see the duchy of Lower Lorraine governed, in the name of the emperor, by the last two shoots of the branch of Charlemagne, the dukes Charles and Othon of France, son and grandson of Louis d'Outremer.

The first was a gallant prince: he may be looked on as the founder of the greatness of Brussels, where he fixed his residence.

After several years of tranquil government, the death of his brother called him to the throne of France; and from that time he bravely contended for the crown of his ancestors, against the usurpation of Hugues Capet, whom he frequently defeated in battle; but he was at length treacherously surprised and put to death in 990.

Othon, his son, did not signalize his name nor justify his descent by any memorable action; and in him ingloriously perished the name of the Carlovingians.
The death of Othon set the emperor and the great vassals once more in opposition.