Christianity constituted one of the fundamental forces shaping the Western political imaginary, influencing both the development of concepts of authority, law, community, and personhood, as well as the formation of political institutions and normative models of public order. At the same time, Christianity has, from its very beginnings, embodied an ambivalent attitude towards politics. Tertullian, while declaring that for the Christian no sphere is more alien than politics, nevertheless insists that he does not disdain the political forum. Idolatry, falsehood, and political ambition, however, are incompatible with the dignity of the Christian politeia, a term by which John Chrysostom designates the comprehensive Christian mode of life understood at the level of customs, culture, religion, social norms, and style of living. Political modernity, together with the processes of secularisation, emancipation, and pluralisation, profoundly transformed the relationship between Christianity and politics, turning it into a lasting object of both theoretical and political contestation. Can Christianity still be regarded as an enduring source of the concepts that organise Western reflection on authority, community, law, personhood, legitimacy, and history? What does Christian politics mean, and is such a politics possible at all? Does the early Christian conviction — that within politics no one can remain pure among the impure — still retain its validity today?