Two networks transformed the early modern world. The first was the Iberian network of discoverers and conquerors that helped usher in an age of European world domination and colonialism. The second was facilitated by a new technology, printing, which helped unleash the huge religious and political disruption we know as the Reformation. What Niall Ferguson describes as a “religious virus that came to be known as Protestantism” disrupted an ancient ecclesiastical hierarchy, fractured into many pieces Europe’s Catholic Christianity, and ushered in a long era of violent conflict. This chapter investigates religious networks within the Lutheran, Reformed, and Radical wings of the Reformation and highlights the formation, evolution, suppression, and ultimate survival of the Jesuit Order as a classic transnational network within Catholic Christianity.