In this chapter, we consider which causes of growth (e.g. human capital, taxation, colonies) were the main factors in moving to modern (sustained) economic growth. The proximate factors are of a Smithian (commercialization) and Northian (institutional change) nature. Unsurprisingly, the importance of each factor varies by country. However, trade/empire, urbanization, forced and free labour, and government power were important in both positive and negative ways, depending on the economic and political structure of the country in question. Noticeable are institutions, which played an interaction role, especially when the institutional framework of a country relied on the coexistence of both “Eastern” and “Western” institutions. Further, we discuss the effect of the demographic transition on human capital formation. After some time, human capital growth began to depend on technology (i.e. increasing income) rather than on fertility, thus obscuring the role of the latter in economic growth.