Deportation is an ancient practice, for example: Khosrau I, Sassanid King of Persia, deported 292,000 citizens, slaves, and conquered people to the new city of Ctesiphon in 542 C.E.The term expulsion is often used as a synonym for deportation, through expulsion is more often used in the context of international law, while deportation is more used in national (municipal) law.