 He finally succeeded in c. 641, when Leuthar, Duke of the Alamans killed Otto under Grimoald's, and we must assume, Cunibert's orders.Grimoald then became mayor of Austrasia.His power at this time was extensive, with properties in Utrecht, Nijmegen, Tongeren and Maastricht; he was even called 'ruler of the realm' by Desiderius of Cahors in 643.