The fortress of Louisbourg, founded in 1713 by French settlers from Placentia, Newfoundland, and named after King Louis XIV, was a major French stronghold in North America. Located on the eastern shore of Île Royale (present-day Cape Breton Island, Nova Scotia), it commanded the entrance to the Gulf of Saint Lawrence and ultimately access to the Saint Lawrence River. In 1745, during King George's War (1744–48), as the North American part of the War of the Austrian Succession (1740–48) is known, the British captured the fortress. It was returned to France in 1748 under the terms of the Treaty of Aix-la-Chapelle and remained in French hands until 1758 when, during the Seven Years War (known in North America as the French and Indian War), it was again captured by the British. The fall of the fortress led to the French loss of Quebec and ultimately of all of Canada. In both 1745 and 1758, colonial militia from New England attached to the British Army played a vital role in the sieges of Louisbourg. Louisbourg Square in Boston is named after the battle of 1745. This map depicting the harbor, fort, and town of Louisbourg, along with the surrounding countryside is by Jacques-Nicolas Bellin (1703−72), a prolific cartographer attached to the French Marine Office. Bellin’s maps and atlases reflect the careful mapping of bays, seas, and harbors that characterized 18th-century French naval cartography. The map is from the collection of the geographer Jean-Baptiste Bourguignon d'Anville (1697–1782). It was given to King Louis XVI in 1782 and deposited in the National Library of France in 1924. Scale on the map is shown in toises, an old French unit of measurement; one toise equals about 1.95 meters.