In 814, Louis the Pious installed Berengar as Count of Toulouse in succession to Raymond Raphinel who had been appointed by Charlemagne.
Berengar appears as a missus dominicus of Louis in May 825 and then in 827 in the six counties of Rheims, Soissons, Senlis, Beauvais, Laon, and Catolonis and the four bishoprics of Amiens, Cambrai, Saint-Pol-sur-Ternoise, and Noviomacensem.
Finally, in the autumn of the same year, successive victories by the imperial forces compelled Pepin and Bernard to appear before the Emperor (October) to plead for peace.
In 833, Aznar I Galíndez, Count of Urgell and Cerdanya, usurped the counties of Pallars and Ribagorza from under Berengar's rule.
In 834, when another rebellious son of the emperor, Lothair, was defeated, Bernard, having fought on the side of Louis with Pepin, reclaimed his old domains as the price of his support.