Prophecy also played a key role when the Wars of the Roses broke out between the Houses of York and Lancaster in the 1450s. The Yorkists used the prophecies of Merlin to support Edward IV’s claim to the throne. The Lancastrians interpreted the same prophecies to mean that their candidate, Henry VI, deserved the crown. One Yorkist manuscript, a sumptuous scroll now in Oxford’s Bodleian Library, features a circular array of insulting names for Henry VI. The names, in English and Latin, include “usurper,” “fool,” and “scoundrel,” as well as “white dragon,” a symbol for the Saxons—always the antagonists in British prophecy. The Yorkist scroll was not meant to win hearts and minds. It was meant to stoke partisan rage.

Prophecies were highly imaginative texts. Knights, heraldry, dragons, double crosses: The genre offered an intoxicating blend of fantasy and realism. One Yorkist prophecy in alliterative verse, found in two Bodleian manuscripts, takes the form of an imagined interview between an English member of Parliament and God. The MP asks what will happen to the realm, and God conveniently foretells the defeat of the Lancastrians, represented as treacherous Saxons. Some of the predictions in prophecies referred to the near future (like FiveThirtyEight’s election forecast), but most of the action amounted to history in the future tense. This was writing that wins consent for a hostile takeover; writing that justifies political violence; writing that kills.

Prophecy wasn’t just an early form of infotainment. It was an instrument of colonization. Some of the earliest recorded prophecies in Britain appeared in the 12th century, in a Latin historical narrative written by a Welsh cleric named Geoffrey. But prophetic style quickly spread from Latin and Welsh to English, and from the margins to the centers of British political power.

By identifying as Britons rather than Saxons, English elites used prophecy to legitimize their rule over the Irish and Welsh and their aggressions against the Scottish. The English projected themselves as spiritual victims of the imperialism of their own ancestors, the Anglo-Saxons. Another Yorkist scroll, held by the British Library, ends with an English passage in which an angel predicts that the Britons will not inherit the island until the Saxons become as sinful as the Britons had been before. The passage aims to galvanize the political will of English readers, not to elicit sympathy for real Celtic peoples. Prophecy rewrote history. The language of the vulnerable was weaponized against the vulnerable.

In the mouths of Welsh rebels and English peasants, prophecy was social protest. In the hands of the ruling classes, it became propaganda. In the 15th century, English kings and parliaments began passing laws against ‘false’ prophecy, in effect criminalizing prophecy without official authorization. The earliest laws claimed to be about other things: vagrancy, civil disorder. They claimed to restrict prophecy only incidentally, as it related to pressing social problems. But the laws were really acts of pre-emptive censorship.