WOLFGANG KELLER, CAROL H. SHIUE
Abstract: The Zollverein was arguably the most important free trade agreement of the nineteenth century. Although 1834 is the official date of the Zollverein’s establishment, member states joined in a non-random sequence over several decades because the benefits of becoming a member increased, both as the size of the union increased, and as membership in the union became increasingly important for accessing foreign markets. We incorporate the endogenous effects of accession into an estimate of the economic impact of the Zollverein customs union. Our estimated effects are several times larger than simple estimates that do not take these effects into account.