This paper advances the importance of degree of gender-egalitarianism embedded in inheritance rules in determining state capacity at its early stages during medieval time. We present a theoretical model whereby state capacity building permits to raise taxes and overcome rivals. It accommodates dynasties in its simplest form and introduces inter-state marriages of landed heirs. On the one hand, dynastic continuity —of utmost importance to European medieval rulers— directly encourages state building. Gender-biased inheritance rules favouring men historically maximise the likelihood of dynastic continuity. We weigh this effect against the indirect impact of more land-merging marriages under gender-egalitarian rules. Contrary to the literature, our results suggest that gender-egalitarian norms —offering low probability of dynastic continuation— promote state capacity in the short run more than gender-biased norms. In the long run results are reversed, providing a rationale for the pervasive European tradition of preferring men over women as heirs.