In highly secularised and plural societies, Catholic secondary education faces the task of engaging with diverse worldviews and backgrounds among both students and teachers, while remaining faithful to its own Catholic foundations. The Catholic identity associated with its official recognition as a Catholic school carries normative implications that, in secular contexts, have proven difficult to integrate explicitly into everyday educational practice, often leading to a more implicit or reduced articulation of Catholic identity. This paper proposes a renewed perspective on the Catholic identity of Catholic secondary education, informed by the thought of Pope Francis. A central inspiration within this perspective is Francis's metaphor of the polyhedron, in which unity is grounded not in uniformity but in a diversity that respects the freedom and irreducible dignity of each person. Within this metaphor, dialogue is not merely an exploration of difference that ultimately reinforces one's own position, but a disposition of openness in which one is willing to learn from the other and to be enriched through encounter. The paper explores how this perspective opens up new possibilities for a meaningful articulation of the Catholic identity of Catholic secondary education in secularised and plural societies such as the Netherlands, with particular attention to institutional positioning, pedagogical orientation, and the curricular development of religious education.