The Mediterranean, both a sea and a theatre, has served throughout history as a fundamental crossroads for the political-religious dynamics and international tensions that characterize the various worlds, east and west, south and north, that meet in this basin. Starting from these premises, the present work examines - within a chronological span that goes from the conclusion of the Second World War to the end of Pius XII’s pontificate - the contribution offered by the Holy See and by Catholics from different national contexts in deciphering the role of the Mediterranean Sea within the wider global context. As such, it constitutes a reflection on this geographical space with its peculiar cultural, economic, political, and religious realities by highlighting the role played by the Mediterranean in the elaboration of visions and projects of civilization. This work is the fruit of a wider research programme called Occidentes - Horizons and projects of civilization in the Church of Pius XII . It brings together the work of seven historians from different European Universities.