Instead of seeking a major battle, as his predecessors had done, Charles chose a strategy of attrition, spreading the fighting at every point possible. The French and Castillan navies destroyed an English fleet at La Rochelle in 1372. Then, du Guesclin launched destructive raids against the coasts of England, naval reprisals to the English chevauchées. Bertrand du Guesclin, appointed Constable of France in 1370, beat back a major English offensive in northern France with an unnerving combination of raids, sieges, and pitched battles. He notably crushed Robert Knolles at the Battle of Pontvallain.