The Battle of Tertry was an important engagement in Merovingian Gaul between the forces of Austrasia on one side and those of Neustria and Burgundy on the other. It took place in 687 at Tertry, Somme. The powerful Austrasian mayor of the palace, Pepin of Herstal, had concluded peace with his Neustrian counterpart, Waratton, in 681. However, Waratton's successors had renewed the conflict between Austrasia and Neustria which was common in times of disunion: though the Frankish realm was then united under Theuderic III, who inherited Austrasia in 679. The king, born and raised in Neustria and a Neustrian at heart, and the nobles of Neustria and Burgundy, under their mayor, Berthar, invaded Austrasia territory. Berthar and Theuderic were routed at Tertry and the Austrasians had the field. Thei