The word pagan is ultimately from the same root as peasant, and entered Middle English via Latin pagus ‘country district’. Roman soldiers used paganus (originally ‘rustic, country dweller’) to mean ‘civilian’; early Christians called themselves milites or ‘soldiers’ enlisted in the ‘army’ of Christ, and used paganus to mean ‘heathen’ (i.e. not part of that ‘army’). The word heathen probably developed in a similar way, coming from an adjective meaning ‘inhabiting open country, savage’.