Does a country’s experience with centralized statehood raise income, or does that experience proxy for the non-state institutions that precede statehood? We argue that the answer is non-state institutions, such as customary law, property arrangements, and decentralized enforcement. This private governance predates the state and promotes coordination and exchange. It also supplies the foundation on which durable states form. Thus, private governance is positively correlated with state experience and with income. As a result, omitting it from state antiquity estimations biases the estimated return upward. To test this claim, we build a private governance index from the coding of early institutions and regress log GDP per capita on both private governance and state antiquity. Adding private governance reduces the ancestry-adjusted state antiquity coefficient by up to 62% and weakens or removes its statistical significance. Private governance has a positive and significant coefficient. We also add squared terms to test for diminishing returns and the robustness of the optimal level of state antiquity identified in prior literature. We find that the optimal level is below prior estimates, and once we include private governance, an optimum cannot be precisely identified. Private governance, however, shows little evidence of diminishing returns. Collectively, the results suggest that state antiquity has no robust association with income once private governance is included, while private governance’s association is large, positive, and significant.