The Horn of Africa distinguishes itself from other regions of Africa by the prevalence and longevity of its multiple conﬂicts. It has been the scene of two of Africa’s longest wars, the thirtyyear liberation struggle in Eritrea and the equally protracted war between North and South Sudan. In both cases, settlements to end the wars involved secession and the creation of new states, a radical solution that bucked the trend of diplomatic practice elsewhere in Africa. In neither case has this solution produced lasting peace and security. A host of unresolved issues – boundary demarcation, citizenship, trade and resource sharing – have ensured that political tensions and episodes of violent conﬂict continue to characterise relations between the former adversaries after separation.