Contemporary debates about whether the right of emigration entails a corresponding right of immigration often address this question in terms of a rights asymmetry. They focus on three interrelated aspects of rights theories which are at stake in international migration: (1) how rights relate to duties; (2) how the concept of a right depends upon its exercise; and (3) if certain rights entail other rights. This paper problematises the asymmetry and argues that one of the pioneering instantiations of individual rights in international law - the ius emigrandi, enshrined in the treaties of Westphalia of 1648 - indeed suggests a correlation between the right to emigrate and a right to stay that has been forgotten. Although unexplored, this historical case seems to point to a practical, and hence theoretical, co-dependency between what I refer to as ‘twin rights’. Hence, I ask if this is a case of rights symmetry that has withered away with time.