<p>This thesis is the biography of John Prestall (c.1527-c.1598) an unsavoury, nefarious, spendthrift, Catholic gentleman from Elizabethan England. A conspirator, opportunist informer, occult conjurer, conman and alchemist, Prestall's biography provides an alternative perspective from which to view Elizabethan history, exposing the dark fringe of the Elizabethan Court and the murky political underworld it attracted. In the polarised politico-religious ferment of late Tudor England, Prestall perennially in debt, utilised his occult powers for his own ruthless self-interest and preservation. Always looking for the best deal, he oscillated between using sorcery and astrology in conspiracies against both Mary I and Elizabeth I, and then traded alchemical promises with members of the Elizabethan establishment for patronage, pardons, and returns from exile. Through an examination of the surviving manuscript correspondence and contemporary print material, this thesis situates Prestall in the broader context of Elizabethan England and uses his life as a conduit linking together a sequence of previously unrelated plots, conspiracies and patronage relationships. Prestall's life, as documented in the manuscripts, was not primarily directed by his Catholic faith which played a secondary role to his search for the best deal and cure for his debt-ridden circumstances. This presents an interesting contrast to members of the Elizabethan regime whose Protestant ideological view of the Catholic-Protestant clash directed many of their actions. This biography explores Prestall's use of conjuring and alchemy to demonstrate the important influence magic had in Elizabethan political conspiracies and Court politics. Within a society whose belief system held magic to be an inherent part of the natural world, Prestall unscrupulously used his astrological and alchemical talents to whatever ends he thought would provide him the biggest payoff.</p>