Herman fought in several important battles supporting his brother Godfrey "the childless", who was Duke of Lower Lotharingia.
Another brother of theirs, Gozelon, held another Lotharingian border position against Flanders at Antwerp, and later became duke of both Lower and Upper Lotharingia.
As explained in the medieval account of the Deeds (Gesta) of the bishops of Cambrai: It has been proposed (for example by Wampach) that Herman might be the same man of that name who held counties in what is now Germany, in the Eifelgau in the 10th century but the identification is likely to be wrong.
[3] In 1013, Herman was present at Hoegaarden on the side of his brother Duke Godfrey the childless, defending against an attack of Lambert I, Count of Louvain on behalf of the prince-bishop of Liège.
[5] After this success, the bishop of Cambrai, Gerard, reluctantly gave permission for Herman's daughter to marry Lambert's nephew, Reginar V, in the interests of peace.