Most people agree that acts of conquest or forced annexation constitute a wrong and that this wrong calls for rectification – ideally, through restitution. At the same time, however, it is a well-known fact that the vast majority of existing states are the product of a history made up of conquests and forced annexations, and few people appear to believe that this fact calls into question their legitimacy. How can these two seemingly conflicting views be reconciled? Exactly what does the wrong committed by acts of conquest or forced annexation consist of? And should this wrong not always call for rectification? This paper will address these questions by focusing on the temporal dimension of territorial rights, and more specifically, by examining whether, and if so to what extent, the validity of territorial claims can be affected by the passage of time and by changing circumstances.