Abstract: We assemble a dataset on technology adoption in 1000 BC, 0 AD, and 1500 AD for the predecessors to today’s nation states. Technological differences are surprisingly persistent over long periods of time. Our most interesting, strong, and robust results are for the association of 1500 AD technology with per capita income and technology adoption today. We also find robust and significant technological persistence from 1000 BC to 0 AD, and from 0 AD to 1500 AD. The evidence is consistent with a model where the cost of adopting new technologies declines sufficiently with the current level of adoption.