Internal Dobrujan Revolutionary Organisation

The Internal Dobrujan Revolutionary Organisation (Bulgarian: Вътрешна добруджанска революционна организация; Romanian: Organizația Revoluționară Internă Dobrogeană) or IDRO was a Bulgarian nationalist and revolutionary organisation active in Romanian Dobruja from 1923 to 1940. It was labeled a terrorist organization by the Romanian government, though in Bulgaria it was regarded as a liberation movement.

Source: Wikipedia — Internal Dobrujan Revolutionary Organisation (CC BY-SA 4.0)