This chapter argues that both the causal elements of domestic/state political leadership, supranational competition, and cosmopolitical normative activism, together with the constitutive element of a ‘normative power’ self image, are important in understanding the EU as a Minervan power. It introduces constitutive and causal theories, the internal origins of the EU’s norms, EU normative principles, and considers the EU’s external practices in action in order to understand the EU as a Minervan power in global institution building. The chapter illustrates this through the EU notion of “effective multilateralism” embracing the active diplomacy of states, the strengthening of supranational and international institutions, and the engagement with the cosmopolitical and transnational activists that capture the EU as a Minervan power in global institution building.