A scarce 17th century sea chart of the Celtic Sea

A fine sea chart of the Celtic Sea, orientated with north to the left. The title cartouche features Nereus and his children, the Nereids, carrying cross staffs and an astrolabe, all important navigational tools.
Marking the south coasts of Ireland Wales, Cornwall, Brittany and the north coast of Spain to Cape Finisterre, its purpose is to show the approaches to the English Channel, an important waterway for the Dutch East India Company. The route was notorious when determining latitude at sea was difficult: indeed it was when a British fleet crashed into the Scilly Isles in 1707 that the famous 'Longitude Prize' was launched.