Forced transfers and deportations of civilian populations are a persistent theme in atrocity crimes. Criminalizing forced displacement not only responds to a major human rights and atrocities problem which is not directly covered by either refugee or international human rights law; it can also serve an important deterrent effect. And yet a critical and enduring question has been around the nature of the relationship between the two offenses of deportation, in which a border is crossed, and forcible transfers, in which a border is not. While both are recognized today as crimes against humanity, the conventional story is that deportations have a much longer and more enduring history than forcible transfers. We argue that this is wrong, and that practice from the Nineteenth century through Nuremberg viewed ‘deportation’ as encompassing both forms of crimes. The loss of this history, however, has meant that in recent times the ICTY, ECCC, and the ICC have had to in effect reinvent the wheel of how forcible transfers are understood and how they are differentiated from deportations as a distinct crime. While a clear conception of forcible transfers as a crime against humanity is now developing in international criminal law, this has limited the number of prosecutions in spite of the fact that this provides a critical accountability mechanism.