Theuderic III, born in the year six hundred fifty-seven, was a notable monarch of the Franks during the tumultuous seventh century. His reign was marked by significant political maneuvering and the influence of powerful figures, particularly Ebroin, the Mayor of the Palace. Theuderic first ascended to the throne of Neustria in six hundred seventy-three, following the death of his brother Chlothar III, but his rule was short-lived as he was soon displaced by Childeric II of Austrasia.
After the untimely demise of Childeric II in six hundred seventy-five, Theuderic reclaimed his position as king. His reign was characterized by military conflict, notably against Dagobert II, where he achieved victory at the Battle of Lucofao, solidifying his power. Following Dagobert's murder in six hundred seventy-nine, Theuderic was also recognized as the king of Austrasia, further expanding his influence.
In six hundred eighty-one, Theuderic and Waratton, the Neustrian mayor of the palace, established a peace agreement with Pepin of Heristal, the mayor of Austrasia. However, the political landscape shifted dramatically after Waratton's death in six hundred eighty-six. The new mayor, Berchar, initiated hostilities against Austrasia, culminating in a decisive defeat for Theuderic and Berchar at the Battle of Tertry in six hundred eighty-seven. This battle marked a significant turning point, leading to the dominance of Austrasia within the Frankish realm.