Despite recent and past research into the collapse of ancient states and into ancient inequality, the possible role of inequality in collapse has been ignored. Inequality as a potential explanatory factor in civil war and collapse in modern states has been the subject of around 150 flawed regression analyses, from which no consensus has emerged. Data for ancient states is insufficient to enable such quantitative modelling. But case studies of the Egyptian Old Kingdom, the Western Roman Empire and the Classic Maya suggest some role for inequality, although the data is sparse and contentious. Paucity of data probably reflects lack of interest and a recent study (Kohler and Ellyson 2018) shows what can be achieved.