That Dieppe was a major centre of hydrographic progress in the 16th Century was recently chronicled in this Column (see Hydro international 2002 Vol. 6 No. 2). David Ross, a Scot, had emigrated to France where he married and settled down in Dieppe. His son, known as Jean Rotz, became associated with seafarers and became a pilot navigating the vessels of Jean Ango, a maritime entrepreneur, to many distant shores from 1530 onwards. On his final return Rotz compiled eleven regional charts covering the whole known world which he published, together with sailing directions, in a handsome atlas to which he gave the name ‘Boke of Idrography’.
In 1540 Rotz went with his family to Paris where for two years he studied navigation and solicited unsuccessfully at the Court of King Francis II with the hope of becoming the royal hydrographer. Hearing that King Henry VIII of England, who was building up his navy, was prepared to offer generous salaries to those capable of furthering his plans, Rotz at the age of 37, sailed with his family for England in 1542.
Presenting the King with a compass of his own invention, a treatise on navigation and a copy of his ‘Boke of Idrography’, supplemented with a world map on two hemispheres dedicated to the King, was enough to secure his designation as the Royal Hydrographer.
He became well acquainted with the ports and harbours in southern England and advised upon the charting of them, as well as getting involved with ship building for the Fleet. However, when Henry VIII was known to be dying Rotz, fearing for his future, approached the French Ambassador in London, Odet de Selve, to help him to return to France. The King of France, now Henry II, only agreed to accept Rotz as a secret agent bringing with him naval intelligence together with plans of English and Scottish harbours.
To ensure secrecy Odet De Selve was able to arrange with Jean Ango, who had become Vicomte de Dieppe, a simulated arrest at sea; Rotz’s wife and children did not fare so well being arrested at Rye, their port of embarkation, and returned to London from where Odet de Selve eventually facilitated their return to France.
Back in Dieppe Rotz prospered as the leading merchant captain, sending his own ships to seek trade in distant lands and to engage in privateering; he also was engaged in shipbuilding for the French navy.
It seems likely that Rotz had meetings with the Dowager Queen Mary of Guise, widow of James V of Scotland, when she visited her daughter Mary (later Queen of Scots) who was currently living in France. Through this connection Rotz would have been able to regain his ancient rights and privileges, forfeited by his father when he emigrated to France, which were due to him as a descendant of the Royal House of Scotland. Thus by 1559 he was deeply involved in the auld alliance between France and Scotland. He gathered together a French fleet ready to invade Scotland to assist Mary of Guise in her fight against the Scottish Protestants which never sailed as a treaty between the parties was signed in Edinburgh in 1560.
In 1759 Henry VIII’s ‘Boke of Idrography’ was passed from the Royal Library to the British Museum and finally to the British Library where this incomparable early manuscript may be viewed today. The introductory pages are written by Rotz in an anglicised Scots language followed by the eleven charts. They are primarily seamen’s charts showing coastlines, islands, rocks and shoals; whilst on land minute sketches evince the lifestyles, industries and habitations of the native populations encountered by the voyagers.
Rotz describes his charts as ‘Showing the lands and sea coasts of the world in so far as by mariners and other sailors it is known’. Much of the detail of both the coasts and the native populations clearly results from Rotz’s personal observations. A peculiarity of the charts is that Rotz always placed south at the top which makes one’s first viewing slightly baffling. They are at a standard scale of 10° of latitude to 123 mm.
In the 1970s the late Viscount Eccles, after inspecting the ancient atlas, decided to put in hand a limited number of facsimiles for his fellow members of the prestigious Roxburghe Club. In the beautiful reproduction by Oxford University Press a chart index sheet has been included which shows how the eleven world charts overlapped one another as in the best schemes of modern day charting. The plates are preceded by an explanatory text edited by the late Dr Helen Wallis; a former Librarian of the Map Room at the British Library who was always ready to help even the most amateur of cartographic historians. It is from her Introduction to the facsimile atlas, together with her splendid essay about Rotz in the magazine ‘The Map Collector’, that I found all my information about this early hydrographer.
On 8 June 1982 Her Majesty the Queen and the Duke of Edinburgh presented to President and Mrs Reagan one of the facsimiles of this famous atlas.
Helen Wallis ‘The Rotz Atlas Ð A Royal Presentation’ - The Map Collector, Issue No. 20 Sept. 1982