In the months following the start of the full-scale Russian invasion of Ukraine in February 2022, international observers were able to note how in the official state discourses in both Russia and Ukraine the war was predominantly being shaped around identity issues. Adopting a long-term perspective, in this paper we will devote our attention to the development and dynamics of what we will describe as "identity regimes", i.e. a set of narratives and policies promoted and shaped by Russian and Ukrainian officials in post-Soviet times in order to redraw the borders of their respective political communities. As we will see, the case of the war in Ukraine in 2022 shows how the current collision of the incompatible historical narratives over the attributes of the Ukrainian and Russian political communities has followed a gradual crystallisation of their respective narratives in oppositional terms over the last decade. A special focus will be devoted to the dynamics following the start of the war in Donbas in 2014, when the repertoire of categories around language and memory practices in use today eventually came to be shaped along diverging lines. Furthermore, the intersection of official and 'unofficial' actors and discourses in structuring the respective identity regimes around the decolonization paradigm in Ukraine and the 'restoration of historical Russia' in the Russian Federation in 2014-2022 will be under scrutiny.