The evolution of European Christianity from the Constantinian era to the Second Vatican Council represents a profound shift in its role and self-understanding within society. Once a dominant force in public life—often termed "Christendom"—Christianity viewed itself as the exclusive interpreter of reality, marginalizing alternative perspectives. However, with the rise of pluralism, a defining feature of modern European societies, this monolithic view began to dissolve. Cultural, religious, and social diversity gradually reshaped Christianity, prompting a transition toward a more open, inclusive form of faith. This shift marks the emergence of a "Christianity of porosity," where faith embodies a hospitable and dialogical spirit, reminiscent of early Christian missionary openness. Instead of seeing diversity as a threat, this approach embraces it as a source of mutual enrichment, facilitating deeper encounters with the divine through diverse human experiences. Pope Francis exemplifies this transformative vision. His teachings emphasize moving beyond moral rigidity to a focus on joyful proclamation, grounded in compassion and inclusivity. Documents such as Evangelii Gaudium, Amoris Laetitia, Laudato Si', and Fratelli Tutti advocate a Church that values goodness in human vulnerability, champions ecological responsibility, and upholds universal fraternity as essential to human dignity. By fostering spiritual discernment and embracing diversity, this renewed Christianity seeks to engage meaningfully in a pluralistic, globalized world, adapting to the spiritual and social challenges of contemporary life.