Having a ‘title to govern’ is critical for regime survival. Authoritarian rulers have also attempted to legitimise themselves as justified rulers. Numerous case studies have examined rulers’ collective efforts to explain their right to govern (legitimacy claims, or legitimation). This thesis tries to examine how the ruler’s seizure of power shapes legitimation capacity in order to gain a thorough grasp of the relationship between legitimation and regime resilience. Using comparative historical case studies of Vietnam, Mongolia and North Korea, this project argues that regimes with indigenous political origins have institutional legacies that are advantageous for engineering legitimation claims, such as strong sub-party organs, effective military and security section control, and collective social norms among political elites during violent revolution. By contrast, an externally imposed political origin lacks these institutional benefits. When rulers face regime crises, these two distinct legitimation claim mechanisms help explain regime resilience or failure. This thesis contributes to the burgeoning literature on authoritarian legitimacy and resilience, and it also expands our understanding of political changes in divergent post-communist countries throughout East Asia.