There has been long-run divergence in the world economy. Some economies have moved ahead and others have fallen far behind. Former colonies such as the USA, Canada and New Zealand or Asian economies such as Japan, Singapore and Korea moved up the income ladder. Other countries such as Argentina, the Ottoman Empire and the Russian Federation slipped downward. For a better understanding of development, we are interested in why some countries or societies forge ahead in given periods, while others stagnate or fall behind.