In 2013 the whistleblower Edward Snowden revealed a surveillance programme called PRISM, within which the United States National Security Agency (NSA) had accessed and analysed the metadata from phone calls, emails, and other digital data stored by Verizon and nine internet companies. This article seeks to show that surprisingly deep insights can be gleaned from metadata by applying a range of easily available network-analysis algorithms to a body of metadata generated by another government. The source is the British State Papers (now digitized at State Papers Online), which contain 132,747 unique letters from the period between the accession of Henry VIII and the death of Elizabeth I. An analysis of this archive shows us that we can observe not only broad patterns of communication but also anomalous behaviour, and can make predictions about people likely to be trading in conspiracies or illicit intelligence. These discoveries demonstrate the power of such methods for the study of history. This power, however, is merely a shadow of that wielded by government bodies and private companies and therefore the findings also act as a warning about the potential uses and abuses of the metadata we generate with each of our digital communications
