burgomaster of Basel who, at the close of the Thirty Years' War, represented the Swiss Confederation at the Congress of Westphalia (Westphalia, Peace of) (in Münster, 1647–48), where he secured European recognition of the confederation's independence and Habsburg renunciation of all claims to Swiss government.

A public notary, Wettstein entered the Venetian army in 1616 to escape his debts, wife, and family. Gradually gaining political prominence in Basel, he was elected burgomaster in 1645; he was officially chosen the following year to represent the Swiss Confederation at the impending peace conference at Münster. At the conference he won recognition of Swiss sovereignty and of his own diplomatic skill. Later, at Vienna (1650), he secured an imperial reaffirmation of complete Swiss autonomy.

In his capacity as burgomaster, Wettstein brutally suppressed a local peasant insurrection in 1653. He participated in the peace negotiations following the internecine Villmergen wars and opposed—ultimately without success—the continuing Swiss alliance with France.