Abstract. – The “Gilgamesh” epic presents a thought experiment about succession and political stability. Although knowledge of the traditional system of the transfer of political power in Mesopotamia is far from unequivocal, historical. and archaeological evidence points to challenges from competing lineages and from powerful usurpers from the periphery. To extinguish rival claims, Gilgamesh adopts a radical solution: he exercises the droit du seigneur. In effect, he is the 5th king of Uruk but only the 2nd born in the city and the first to found a dynasty. By placing his sons in other lineages, he delegitimises competing claims from rival lineages and establishes a patrilineal dynasty. Gilgamesh’s adventures in space (the raid to the West) and time (the quest for immortality) are merely framing devices for putting in place the events by which his biological strategy of ius primae noctis is revealed to be the only real means of strengthening the urban centre’s relatively weak hold over its dominant periphery. [Mesopotamia, Gilgamesh, kingship, patrilineal succession, women]