John Dee, who for awhile had been one of the most famous and influential men in England.
Doctor Dee was a learned man who combined studies in mathematics, cartography and astronomy with studies in alchemy, astrology and magic. This was not an uncommon combination in those times. Dee first made his name with the mathematics of navigation, guiding British ships in the era of discovery.
Like Prospero, he loved books. His personal library was reputed to be one of the greatest in England. He drew up a plan for a national library during Queen Mary's reign, though it wasn't adopted.
He later became a highly influential court astrologer to Queen Elizabeth. He wrote on mathematics but also on occult documents. He created and interpreted a glyph which expressed the mystical unity of creation, at a time when such symbols themselves were thought to have power. He later delved more deeply into magic, seeking contact with angelic spirits.
But like Shakespeare, he also was deeply interested in British explorations, especially to the New World. He was an advocate for British imperialism, and is credited with coining the term "the British Empire."
Doctor Dee eventually retired to his summer home in Mortlake, where he found his library and his instruments had been looted. According to writer Peter Ackroyd, at some point he announced that he had burned his books on magic.
Dee lived his last years in Mortlake with his daughter Katherine. He died in his early 80s, about a year before Shakespeare started writing The Tempest. There seems to be no record of Shakespeare meeting Doctor Dee while they were both in Mortlake, but Dee probably was a topic of conversation in that small town. Shakespeare would have taken note of Doctor Dee years before as a unique and powerful figure in the court of Elizabeth, . It seems reasonable that Doctor Dee was a major model for Prospero.