Crowding on slave ships was much more severe than historians have recognized, worsening in the nineteenth century during the illegal phase of the traffic. An analysis of numerous illustrations of slave vessels created by then-contemporary artists, in conjunction with new data, demonstrates that the 1789 diagram of the British slave ship Brooks—the most iconic of these illustrations—fails to capture the degree to which enslaved people were crowded on the Brooks, as well as on most other British slaving vessels of the eighteenth century. Five other images of slave ships sailing under different national colors in different eras further reveal the realities of ship crowding in different periods. The most accurate representation of ship-board conditions in the eighteenth-century slave trade is in the paintings of the French slave ship Marie-Séraphique.