The Selden Map is a story of both failed and successful translations. Unlike the universalist aims of Mercator’s projections, the topological system of routes defined by the Selden map was designed to translate between systems of trade, something that would have appealed to the author of Mare Clausum. The talk will begin by examining what the depiction of the Pratas, Spratley and Paracel Islands in the South China Sea on the Selden Map reveals about the encounter between Portuguese and East Asian mapping traditions. It will then discuss how Selden in the 1650’s and Thomas Hyde and Shen Fuzong in the 1680’s tried to contextualize and translate the navigational elements on the map. Finally, it will examine what the recent restoration tells us about the technical design of the map, suggesting that the Selden map offers a key to how mathematical and navigational techniques were translated not only in relation to Europeans but also among Chinese, Southeast Asians and even Pacific Islanders. What we have not been able to see before is the Selden map as a global object, one that opens up long-concealed histories of the early modern period and the exchanges that made globalization possible.