This paper shows that the Becker-Woessmann reformulation of the Weber thesis-Protestants were more prosperous in 19th-century Prussia because they had higher human capital-is untenable. Regional variations in the Prussian institutional framework influenced economic outcomes, but Becker and Woessmann's econometric analysis takes no account of these variables, which suggests that their instrumental variable-distance to Wittenberg, a spatial variable-is invalid. When these regional effects are taken into account, 19th-century Prussia provides no evidence that Protestantism increased prosperity by increasing human capital.