We investigate the relationship between exposure to "authoritarian" or "autocratic" institutions for prolonged periods of time and long-term economic development. Specifically, we examine how the length of time a country's regime was authoritarian between 1920 and 2000 is correlated with economic growth and per capita income. We find a moderate though negative effect, even after controlling for other factors. In contrast, we also find that the length of time a country is not subject to authoritarian regimes is positively related to economic growth and the level of per capital income. We claim this evidence is consistent with the thesis that one of the reasons why countries have had difficulty adjusting to life after autocracy is that the human and social capital necessary to make markets "work" eroded under autocratic regimes and takes time to develop afterward.