Five British tribes, the Cenimagni, the Segontiaci, the Ancalites, the Bibroci and the Cassi, surrendered to Caesar and revealed the location of Cassivellaunus's stronghold, thought to be at Wheathampstead, which Caesar proceeded to put under siege.
The root uellauno- is found in many other Celtic names, including those of the goddess Icovellauna; the hero Cassivellaunos, later famous in Welsh legend as Caswallawn; and the Catuvellauni, a tribe of southeastern Britain, whose name may also be cognate with Catalauni (Châlons-sur-Marne) and Catalaunia (Catalonia).