Battle of Tertry

By the 680s real power in the Frankish kingdoms lay with the mayors of the palace, who governed in the name of the Merovingian kings. Waratto, who succeeded the murdered Neustrian mayor Ebroin, made peace with Pepin, but in 686 he was succeeded by his son-in-law Berchar, and Neustrian nobles who opposed Berchar turned to Pepin for help. In 687 Pepin led the Austrasians into Neustria and met Theuderic III and Berchar near Tertry, on the little river Omignon not far from Saint-Quentin. According to the fullest account, in the Earlier Annals of Metz, Pepin first tried to negotiate, then burned his camp at night and took up a new position; when the Neustrians crossed the river in pursuit of what they took for a retreating enemy, the Austrasians fell on them and routed them.

Berchar kept his office for a while — a royal charter of 30 October 688 still names him as mayor — but was murdered late in 688 or early in 689, reportedly at the instigation of his mother-in-law Ansfled. Pepin then became mayor of Neustria and Burgundy as well, keeping Theuderic III on the throne but taking charge of the king and the royal treasure, and governing through his own men, first Nordebert and later his sons; he styled himself dux et princeps Francorum, “duke and prince of the Franks”.

Historians such as Rosamond McKitterick count Tertry among the decisive moments in the rise of the Carolingian house, although the most detailed account of the battle was written in the early 9th century in praise of Pepin’s descendants. From then on, apart from the crisis that followed his death in 714, his family dominated Francia: his son Charles Martel defeated the Arabs at Tours, and his grandson Pepin the Short took the royal title in 751.