Secessionism and irredentism describe processes of withdrawal of a territory and its population from an existing state and the creation of either a new state on that territory or the merging with another state. The contemporary international order – especially in Europe – is characterized by a multitude of these phenomena. Examples include not only cases like East Timor, Cyprus, Pakistan, Yugoslavia, but also more contemporary events like the Brexit. Both phenomena are most often accompanied by conflicts that complicate post-secessionist/irredentist relations with the former rump state. This seminar analyzes which conditions may lead to the establishment of secessionist and irredentist movements, development over time, and under which conditions successful and lasting forms of secessionism/irredentism are possible. A special focus will be put on regional factors that encourage the establishment of secessionist and irredentist forces.