In 717, Charles mustered his army again and marched on Neustria, taking the city of Verdun during his conquest. He met Chilperic and Raganfred again at the Battle of Vinchy on 21 March 717 and was once again victorious, forcing them back to Paris. He then swiftly returned to Austrasia and besieged Cologne, defeating Plectrude and reclaiming his father's wealth and treasure. Charles bolstered his position by installing Merovingian King Chlothar IV in Austrasia as an opposing Merovingian to Chilperic II. Despite not having a Merovingian King for around 40 years in Austrasia, Charles' position was clearly weak at this time and he required the support of the established Merovingians to gather military support. Even despite his weaknesses, Charles' recent success had made him a greater political entity, as such Chilperic and Raganfred could not win a decisive victory against him. So, in 718 they to sent embassies and won the support of Duke Eudo of Aquitaine whom at their request mustered 'a Gascon army' to face Charles. In response, Charles brought an army to the eastern Neustrian borders and faced Duke Eudo in battle at Soissons. Duke Eudo, realising he was outmatched, retreated to Paris where he took Chilperic and the royal treasury and left for Aquitaine. Charles pursued them, according to the "Continuations", as far as Orleans, but Eudo and the Neustrians managed to escape. In 719, King Chlotar IV died and was not replaced, instead Charles became the primary authority in Francia. He established a peace treaty with Duke Eudo that ensured Chilperic II was returned to Francia; thereafter, until Chilperic's death in 720 at Noyon, the Kingship was restored with Carolingian control and Charles became the "maior palatii" in both Neustria and Austrasia. Following Chilperic II's death, the Merovingian King Theuderic IV, son of Dagobert III, was taken from Chelles monastery and appointed by the Neustrians and Charles as the Frankish King.