This article contributes to research on commemorative naming strategies by presenting a comparative longitudinal study on changes in the urban toponymy of Leipzig (Germany) and Poznań (Poland) over a period of 102 years. Our analysis combines memory studies, linguistic landscape (LL) research and critical toponymy with GIS visualization techniques to explore (turnovers in) naming practices across time and space. The key difference between the two localities lies in the commemorative pantheon of referents—events, people, and places inscribed as traces of a hegemonic national past—that are replaced when commemorative priorities change. Other patterns are common to both study sites. Notably, in both Poznań and Leipzig, peaks of renaming occur at the threshold of regime change, after which commemorative renaming activity subsides. We report on our findings and propose methodological guidelines for analyzing street renaming from a longitudinal, transnational, and interdisciplinary perspective. (Collective memory, critical toponymy, memoryscape, linguistic landscapes, encoding of ideology, comparative analysis of Eastern Europe, longitudinal analysis, commemoration, GIS visualization)*