This rare chart of the Sea of Marmara was made at a critical time in the region’s history. The Sea of Marmara, the Black Sea, and the Bosporus and Dardanelles straits are of central importance for the governance of Istanbul, and so the conflicts of the Ottoman Empire often rested on a detailed understanding of the waters. In the 1840s, joint Ottoman and Russian forces launched an expedition under Captain Manganari to complete the first systematical survey of the Black Sea using triangulation, which “deserves to be counted among the greatest contributions to the cartography of the sea” (King); the results of their work were published as an atlas, which “deserves to be counted among the greatest contributions to the cartography of the sea” (King), ands remained highly influential for over 30 years. During the Crimean War, however, the British navy became involved in the area, and Captain Thomas Spratt was deployed on the Spitfire to create an accurate chart, noting the positions of the allied fleet for the attack on Sevastopol. Spratt was later appointed to the Order of Bath, and subsequently to the Royal Society for his other geographical work.

His chart of the Sea of Marmara shows depth in soundings and isolines, relief in hachures, and identifies important towns, cities and ports. Notes about lighthouses and beacons provide additional information that would prove useful for both sailors and the military. Similarly, the 14 inset views on the upper and lower border allow for a more detailed examination of certain significant coastal areas. The imprint in the lower right corner identifies the engraving of this chart as the work of John and Charles Walker. Walker Cartographers had been responsible for naval charts since the British Hydrographic Office was established in the late eighteenth century, and subsequently produced numerous charts of the colonies. While this map is typical of the nineteenth century naval charts produced by the British Admiralty, it is equally rare, with only two institutional examples – The National Maritime Museum, and the Connecticut State Library.