Berthar

Berthar (also Bertharius or Berchar) was the mayor of the palace of Neustria and Burgundy from 686 to 687. He was the successor of Waratton, whose daughter Anstrude he had married.
Unlike Waratton, however, Berthar did not have peace with Pepin of Heristal. In 687, Pepin defeated him and Theuderic III at Tertry in the Vermandois. Many fled to the nearby abbeys of Péronne and Saint-Quentin. Berthar and Theuderic III withdrew themselves to Paris. Pepin followed them and eventually forced a peace treaty with the condition that Berthar leave his office. In the ensuing quarrels, Berthar killed his mother-in-law Ansfled. Berthar fled. His wife married Pepin's eldest son Drogo, duke of Champagne, and Pepin became the mayor of the palace of Neustria and Burgundy without opposition.
Berthar died in either the Autumn of 688 or early 689.