‘Sanctifying secular wars’ evaluates another category of religious wars: secular wars, in which religious commitment is used to pursue aims largely unrelated to religion. Shinto and Buddhism helped strengthen the Japanese war effort in the Second World War. But Japan fought a war of outward conquest. More often, when religion supports rather than motivates war, this is in situations where two religions, each related to a community more or less defined in other ways, collide. This dynamic can arguably be seen at work in Serbia during the Battle of Kosovo Polje (1389), in Northern Ireland, in Sudan, in the Biafra war in Nigeria (1967–70), and in Sri Lanka.