How does the author use foreshadowing in The Return of Martin Guerre?

In Chapter One, the easy shift in identity of the Daguerre family of Basque ethnicity, to the French family, the Guerres, foreshadows the ability of Arnaud du Tilh to impersonate the missing Martin Guerre. It symbolizes how easy it is to shift identity without the existence of personal records, at the time. The concept of national identity is at the time just beginning, with France on the verge of religious civil
war.