Human ability to manipulate fire and the landscape has increased over evolutionary time, but the impact of this on fire regimes and consequences for biodiversity and biogeochemistry are hotly debated. Reconstructing historical changes in human-derived fire regimes empirically is challenging, but information is available on the timing of key human innovations and on current human impacts on fire; here we incorporate this knowledge into a spatially explicit fire propagation model. We explore how changes in population density, the ability to create fire, and the expansion of agropastoralism altered the extent and seasonal distribution of fire as modern humans arose and spread through Africa. Much emphasis has been placed on the positive effect of population density on ignition frequency, but our model suggests this is less important than changes in fire spread and connectivity that would have occurred as humans learned to light fires in the dry season and to transform the landscape through grazing and cultivation. Different landscapes show different limitations; we show that substantial human impacts on burned area would only have started ∼4,000 B.P. in open landscapes, whereas they could have altered fire regimes in closed/dissected landscapes by ∼40,000 B.P. Dry season fires have been the norm for the past 200-300 ky across all landscapes. The annual area burned in Africa probably peaked between 4 and 40 kya. These results agree with recent paleocarbon studies that suggest that the biomass burned today is less than in the recent past in subtropical countries.human evolution | human ignition | savanna | fire spread model F ire has been a part of the earth system for billions of years (1), but recently-within the past million years at most-humans have provided a new and different source of ignition. Today, fires in all ecosystems are largely started by human ignitions, whether intentionally (for land management or arson) or by accident.From studies in modern systems we know that humans can affect fire regimes via their effects on both ignition (frequency, season, and location) and landscape connectivity. However, we lack an understanding of how these different impacts might have emerged as humans learned to control fire and as they spread throughout the globe. Moreover, the degree to which current human-ignited fire regimes differ from historical, lightning-driven regimes is largely unresolved (2).The question is complicated by the fact that the potential limitations on fire are various and system specific (3), and as one constraint is released, others can come into play. Thus, the number of ignitions can increase without a concomitant increase in area burned (4, 5), and responses of fire to drivers like population density can be nonlinear (6). Most ecosystems in Africa are probably not ignition-limited currently; ignition rates are more than sufficient to burn the available fuel, and climate and landscape connectivity act as the main limitations on fire (5, 7, 8).Interpreting historical human effects on fire regim...