Dudley’s Chart of the Philippines, from the ‘Arcano del Mare’, is hailed as one of the “greatest atlases of the world” according to Wardington. Published in 1646, the map shows the islands of the Celebes Sea, including the southern Mindanao group of the Philippines, the Maluku Islands, and the northern coast of the island of Sulawesi in Indonesia. Not only was it the first sea atlas of the world, but it was also the first to use Mercator’s projection; the earliest to show magnetic deviation; the first to show currents and prevailing winds; the first to expound the advantages of ‘Great Circle Sailing’ – the shortest distance between two points on a globe; and “perhaps less importantly the first sea-atlas to be compiled by an Englishman, albeit abroad in Italy” (Wardington).
Dudley (1573–1649) was the illegitimate son of Robert Dudley, Earl of Leicester and Lady Douglas Sheffield, the widow of Lord Sheffield. He was also the brother-in-law of the celebrated circumnavigator Thomas Cavendish. From 1594-1595, Dudley joined the Royal Navy and led a privateering expedition to South America. In 1596, he commanded the ship Nonpareil in the Earl of Essex’s successful attack on Cadiz, and was knighted for his services.
Despite his successes at sea, Dudley sought to have his legitimacy established at court, but his attempts failed, and he fled to Europe, eventually settling in Florence at the court of the Grand Duke Ferdinand I of Tuscany. In Florence, Dudley put his naval experience to good use; he worked as a ship-builder, consulted on construction projects for harbours and their fortifications. More importantly, it was at this time that he was also writing his magnum opus, a handbook of navigation, the Dell’Arcano del Mare. An early manuscript version of the text survives in the Museo di Storia Naturale, in Florence, in three volumes, two dated 1610. A second, more complete version, dated [c1636-1646] is in the Royal Library, Munich, containing a series of manuscript charts.
The Dell’Arcano is the first printed sea atlas of the world, and the charts form the first series constructed on the Mercator projection, a projection particularly suited to navigation. However, the Dell’Arcano was too large and elaborate for use on board ship. Crafted by the English and other pilots, the charts are generally accepted to be scientific and accurate work for the time. It is assumed that Dudley used the original charts of Henry Hudson, and for the Pacific Coast of America used his brother-in-law Thomas Cavendish’s observations. Notably, the charts were elaborate in style and engraved by Antonio Francesco Lucini through the course of twelve years and five thousand pounds of copper.
After his death, Dudley’s library passed to Ferdinand II, Grand Duke of Tuscany, and much of it resides in the Bibliotheque Nazionale, Florence, including an interesting and important group of English manuscript charts, drawn by John Daniel, while his scientific instruments are to be found in the Museo Galileo, in the same city. Dudley’s Dell’Arcano is one of the most important of all sea atlases and yet it had no heirs and, seemingly, no influence, so it stands alone, a unique and as yet little understood masterpiece.