The Battle of Tertry and the Ascendancy of Austrasia

In 681, Theuderic III, the Merovingian king of Neustria, and his mayor of the palace, Waratton, establish a fragile peace with Pepin of Heristal, the mayor of the palace of Austrasia. This temporary truce, however, unravels following Waratton’s death in 686, when his successor, Berthar, adopts an aggressive stance against Austrasia.

In 687, Berthar, alongside Theuderic III, leads the Burgundo-Neustrian army against Pepin of Heristal in a decisive confrontation at the Battle of Tertry, near Péronne. The result is a crushing Austrasian victory, cementing Pepin’s control over Neustria and Burgundy and effectively shifting the balance of power within the Frankish realm. With this triumph, Austrasia emerges as the dominant force in Francia, with its mayor now the true ruler of the kingdom.

Following Theuderic III’s death, his nine-year-old son, Clovis IV, inherits the throne of Austrasia in 691, though his rule is entirely nominal. Real authority rests with his uncle, Pepin of Heristal, who governs as the de facto ruler of the Frankish state, further solidifying the decline of Merovingian royal power and the rise of the Arnulfing dynasty.