In Dialogue on Miracles, the thirteenth-century preacher and historian Caesarius of Heisterbach tells of a man curious to discover the origin of the migratory swallows that appeared at his house every spring. Catching one of them, he attached a note to its leg that read, “O swallow, where do you live in winter?” The following spring, a bird appeared with a reply attached to its leg: “In Asia, at Peter’s house.”

According to an Aztec myth, the war god Huitzilopochtli sent a group of Mexica on a journey to establish the new center of the world. After some two hundred years of wandering, they saw an eagle resting on a cactus with its “wings stretched outward like the rays of the sun.” Taking the bird to be a divine sign that they had reached their destination, they “began to weep and dance about with joy and contentment.”