Embassy lies at the heart of Christianity. Recall the archangel Gabriel, sent as God’s messenger to Mary in the village of Nazareth. This event alone, described in Luke’s Gospel (1:26–37) and represented in lively pictures and sculptures innumerable times, is enough to remind us of the long historical connection between Christianity and diplomacy. And so it is no surprise that, as a specific literature on the ambassador began to develop in early modern Europe, the analogy between diplomats and angels was very frequently used. The roots of this analogy can be traced back to the writings of the Jewish thinker Philo of Alexandria († c. AD 50), and to the biblical Letter to the Hebrews (1:14), traditionally credited to Paul. It was from the late Middle Ages onward, however, that the analogy really gained currency, in parallel with the development of diplomatic theory and practice.