The apparent mobilizing power of ethnic sentiment in recent African history has been the subject of vigorous debate. Studies that emphasize the centrality of colonialism and the instrumental use of ethnicity have been criticized by a scholarship arguing that the affective power of ethnicity is culturally rooted through longstanding experience and practice, and that both manipulation and invention are constrained by this. This paper contributes to that debate through a discussion of the history of the Mijikenda, one of the “super-tribes” of modern Kenyan politics. It suggests that there were indeed “limits to invention,” but that there was nonetheless substantial entrepreneurship and creativity in the politics of Mijikenda identity. This drew heavily on the productive, discursive tension between tradition and modernity that lay at the heart of colonialism and was drawn into vigorous debates over legitimacy and representation in the “critical juncture” of the final years of colonial rule.