As it progressed, the expedition sought to strengthen France's claim to the territory by marking it at the mouths of several principal tributaries. At each point, a tin or copper plate bearing the French royal arms was nailed to a tree. Below, an inscribed leaden plate was buried, declaring the claims of France. This was a traditional European mode of marking territory, but it might have contributed to Native American anxieties about the intentions of the French, and thus ultimately had a counterproductive effect.