A 16th-century portrait by an unknown artist.
John Dee (1527–1608 or 1609) was an adviser to Queen Elizabeth I. |as well as being a mathematician, astronomer, and astrologer, he trained some of the great explorers in the art of navigation. He studied with Mercator and owned an important collection of maps, globes and astronomical instruments. He developed new instruments as well as special navigational techniques for use in polar regions.
In 1555, he was arrested and charged with “calculating” for having cast the horoscopes of Queen Mary and Princess Elizabeth. Later the charge was changed to treason against Mary. Dee not only managed to clear his name but in 1556 he presented Queen Mary with a visionary plan for the preservation of old books, manuscripts and records and the founding of a national library. Sadly, his proposal was not taken up. Instead, he expanded his personal library at his house at Mortlake in Surrey, tirelessly acquiring books and manuscripts in England and on the European Continent. Dee’s library, a centre of learning outside the universities, became the greatest in England and attracted many scholars. His library was not only the largest in the country but was considered one of the finest in Europe, perhaps second only to that of de Thou.