This article highlights a link between measures for precolonial institutions and ethnic fractionalisation in postcolonial countries. A conceptual explanation is provided for why countries that were more politically centralised in precolonial times should be less ethnic fractionalised in current times. This result is confirmed for a sample of post-colonial countries in Africa, Asia, and the Pacific. This is followed by a comparative case study of in the south pacific countries of Papua New Guinea, Tonga, and Samoa. It is hoped that these results will lead to further empirical work focused at delving deeper into the link between these two measures to better understand what they are actually measuring, and why both are so closely related to economic development.