In the current debate, the notion of identity is frequently castigated as a contrived creation, giving rise to antagonism and hatred. This article aims to counter this thesis on the basis of two cosmopolitan traditions. Cultural cosmopolitanism, particularly in its original formulation as espoused by ancient Stoicism, shows that different cultural identities – ethnic, national, religious – can be not only compatible but also complementary. Conversely, political-institutional cosmopolitanism acknowledges that identities with a socio-economic foundation are inherently conflictual, yet posits that conflicting interests can be resolved within institutional frameworks (particularly the state and the supranational bodies), whose primary function is to manage peaceful coexistence in accordance with established rules. However, the two levels must never be confused. Cultural identities must not assume a political character, and institutions, in turn, must disregard any dimension of identity other than that of citizenship, i.e. adherence to the same system of rules.