This superbly detailed plan shows the Bay of Gibraltar during the Great Siege.

The Great Siege of Gibraltar was an unsuccessful attempt by Spain and France to capture Gibraltar from the British during the American War of Independence. This was the largest action fought during the war in terms of numbers, particularly the Grand Assault of 18 September 1782. It was the longest siege endured by the British Armed Forces, as well as being one of the longest continuous sieges in history.

Faden manages to show much fascinating detail including fire ships, and the dreaded Spanish Floating Batteries. These makeshift craft were built of timber one metre-wide packed with layers of wet sand and declared fire-proof and unsinkable, and were designed to fire on Gibraltar at close quarters. To counteract this the British devised so-called 'hot potatoes' which were cannonballs pre-heated to furnace pitch. Many were doused by the Spanish crews but a rogue hot potato could lie smouldering in the bowels of the ship and the burning cavity would explode into an inferno.

To reinforce the importance of the breaking of the Great Siege, Faden places above the title a 'Roman Obsidional Crown', which during the Roman Republic was awarded to the General who raised a siege.

William Faden (1750-1836) began his career in cartography after taking over the business of Thomas Jefferys, a highly respected British mapmaker. Initially publishing under the name Faden and Jefferys, he followed his predecessor by specialising in maps of North America, resulting in the publication of a collection of them in the 'North American Atlas' in 1777. Twice honoured by the Royal Society for his work, he became Geographer to the King in 1783, and was chosen in 1801 to create and print the first of the Ordnance survey maps.