Sir Robert Dudley, was the son of Lord Robert Dudley, Earl of Leicester, a favorite of Queen Elizabeth I. Legitimate or illegitimate, has been an argument that has been going on for years and it really doesn't matter, for all will agree he was Robert's biological son. Brilliant and ambitious, he became an extraordinarily skilled navigator, engineer, and chartmaker, and aspired to make a major voyage of discovery in the fashion of Sir Francis Drake. Dudley's life was noteworthy, and was, however, a bigamist, privateer, engineer, mathematician, architect and designer of warships and scientific instruments. In 1594-5 he commanded an expedition to the West Indies and the Guiana coast of South America. In 1596 he served as commander of a vessel in the attack on Cadiz for which he was knighted. He fell out of favor at the English court due to his philandering and ill-considered support of the Essex rebellion and in 1605, Dudley, a Roman Catholic, fled religious persecution in England and settled in Tuscany, Italy. After leaving England, he assumed the titles of Duke of Northumberland and Earl of Warwick, and entered the service of the Grand Duke of Tuscany. From 1606 until his death in 1649 he lived in Florence and was an influential member of the Court of the Medicis. under the patronage of the Grand Duke of Tuscany a member of the Medici family - for whom he undertook a series of projects including the draining of the swamps between Pisa and Livorno (Leghorn).

His major accomplishment and his masterwork Dell'Arcano del Mare (Secrets of the Sea), a sea atlas and comprehensive treatise on navigation, shipbuilding, and naval organization, also is renowned as the first atlas of sea charts of the world, on a uniform Mercator projection, was published in 1646 and 1647 just before his death in 1649. A second edition with 146 maps was published by Guiseppe Cocchini in 1661.

The map below is a reduced version of the earliest printed sea chart of the east coast of North America made by an Englishman, and the first to use the Mercator projection. Its maker was, Sir Robert Dudley. Published in 1646, it is generally considered to be the most distinguished of its time. Another example is below this, and for more images of these maps go to the Sir Robert Dudley's Dell'Arcano del Mare (Secrets of the Sea) page.