Wiomarc' H chief of Breton at the time of the revolt of 822 with 825

The capacity of Wiomarc' H seemed to be exerted in the north of the Brittany i.e the Western area of the Domnonée. The use of this name by the posterior Viscounts of Leon trained certain old historians to wrongly see in him the ancestor of the counts de Léon.

We do not know with certainty, if he asserted the royal title because primarily know we it by testimonys of the frank Annalists Eginhard and the Anonymity known as the Astronomer who specify us:

822 the counts of the Steps of Brittany, after the autumnal equinox, threw themselves on the possessions of certain Breton named Wihomarch, which remained in a state of rebellion, and devastated all by the flame and iron (Eginhard).

824 the emperor differed the race which he wanted to make in Brittany, because of the famine which was then felt in all its force. Having finally joined together its troops of all shares, it moved on Rennes, quoted contiguous at the borders of the Brittany. Dividing its army three bodies, it entrusted two of them to its sons Pépin and Louis, reserved the third, penetrated in the Brittany and devastated it by iron and fire. After having employed forty days and more to this forwarding and receipt the hostages whom it had ordered in perfidious Breton to deliver to him it left the November 17th for the town of Rouen (Eginhard).

825 the emperor ordered that one assembled general was held with Aachen in May. A rather great number of Breton lords attended this assembly where he protested lengthily of their tender and their obedience: among them was this Wihomarch, which seemed to have a higher authority, and whose bold blind man audacity and intentions had pushed the emperor to make as we saw a forwarding in Brittany; but as on this occasion he testified repentance to his misdeed, you gave up itself at the discretion of the emperor, this prince obeying only his leaning which involved it with leniency, accommodated it with kindness filled it to you present like all the other Breton ones, and allowed him to turn over in its fatherland (the Astronomer)

But falling down in the ordinary perfidy with its Wihomarch race violated promptly, as it was accustomed to make it, the sworn faith, and did not cease afflicting its neighbors by crushing and the fire until the moment when finally it was encircled and killed in its own residence by the men of the count Lambert (Eginhard).

The revolt carried out by Wiomarc' H, approximately 3 years, was rather short but it had to be sufficiently important to require the intervention of an imperial army ordered by Louis the Piles itself and its two sons.