Since the end of the Cold War, the majority of armed conflicts occurring in the world have consisted of internal conflicts characterized by the increasing involvement of foreign volunteers among non-state actors and, to a lesser extent, among state actors. This phenomenon is not exclusive to the contemporary period as it has occurred throughout history, starting with the American and French revolutions at the end of the 18th century, gaining stronger impetus all through the conflicts of the 19th and 20th centuries. Globalization, the growth of internal armed conflicts with international dimensions, the global spread of information, and the increasing ease of travel gave new significance to this phenomenon, especially after 9/11 in the form of global jihadism. The goal of this paper is to present the development of this phenomenon throughout contemporary history, clarify its conceptual definition, analyze its implications with regard to international law, identify the motivations of foreign volunteers involved in armed conflicts and discuss the contemporary, as well as future perspectives of this phenomenon.
