Since the Great Recession of 2007, research on the causes of economic inequality has been at the centre of both societal and academic debates, also among historians. Whereas most scholars have focused on contemporary and early modern societies, I propose to address this issue by using European rural society in the 14th century as a laboratory to study and explain the high pre-Black Death economic inequality suggested by previous studies. This project explores why, how and to what extent patterns of wealth and income distribution are correlated with economic growth, demographic growth as well as power and socio-property structures in a transforming society. In the 14th century, Western civilisation was on the cusp between late medieval growth and the transformation of its socio-economic and demographic pattern, expedited by the Great Plague (1348). By focusing on quantitative cross-sectional analyses of two fiscal surveys for French Artois and Sienese Tuscany, illustrative regions of the Late Medieval crisis, I will compare new patterns of distribution and I will verify at regional level overall explanatory factors of economic inequality. As such, this study will contribute to a new narrative of the Late Medieval transition based on wealth and income concentration.