Miracles and visions were not the only means by which the divine might communicate with humankind. Rather, to those of a more Augustinian worldview, God had imbued the entirety of Creation with communicative potentiality, an intrinsic ability to serve as a sign. Thus, while both miracles and visions could signify, so could the unusual or uncanny, such as solar and lunar eclipses or earthquakes. However, Christian theologians since the early Church grappled with the long, pre-Christian history of signs and other ‘ways of knowing’, and the association between certain practices and Islam, classical antiquity, and ancient Mesopotamia. Additionally, the increasing scope allowed for naturalising explanations and the pursuit of causation in the Latin Christian intellectual landscape of the twelfth and thirteenth centuries shrank the scope of the potentially significant. A lunar eclipse could be indicative of an impending clash between kingdoms, or it could just be a manifestation of the routine cycle of the planets, signifying nothing. In this chapter, it will be argued that tensions between theologically licit and illicit ways of knowing surface at intervals in crusade narrative, often in discussions of the legitimacy of certain practices or in descriptions of perceived Others. These examples reveal a blurred, shifting boundary between legitimate and illegitimate practice, which authors were required to navigate in order to effectively engage with signs in their narratives.

Interpreting Signs in Medieval Latin Christendom

God's communication with humankind had considerable scriptural precedent. As the twelfth-century polymath John of Salisbury comments in his Policraticus, one should not doubt that certain astounding things can be signs, since Christ advises in the Gospel of Luke that ‘there shall be signs in the sun and in the moon and in the stars’, and ‘there shall be great earthquakes in divers places, and pestilences, and famines, and terrors from heaven; and there shall be great signs.’ These sorts of signs, often presented in the form of natural phenomena such as earthquakes, were indicative of events temporally past, present and future, and spatially near and far. For example, William of Poitiers records how an appearance of Halley’s comet foretold the defeat of Harold Godwinson in 1066.