Mont Saint-Michel is a rocky tidal island 247 acres in size, and is a commune in Normandy, France. It is located approximately one kilometre (just over half a mile) off the country's north-western coast, at the mouth of the Couesnon River near Avranches. The islands highest point is 92 metres (301 feet) above sea level. The population of the island is 44, as of 2009. The island has held strategic fortifications since ancient times, and since the 8th century AD been the seat of the monastery from which it draws its name. Mont Saint-Michel and its bay are part of the UNESCO list of World Heritage Sites. More than 3,000,000 people visit it each year.
Mont Saint-Michel was used in the 6th and 7th centuries as an Armorican stronghold of Gallo-Roman culture and power, until it was ransacked by the Franks, thus ending the trans-channel culture that had stood since the departure of the Romans in AD 460. From roughly the 5th to the 9th century the westernmost portions of the Armorican peninsula emerged as the region of Brittany, which initially included the Contentin Peninsula to the northeast along the coast from Mont Saint Michel.
The mount gained strategic significance in 933 when William "Long Sword", William I, Duke of Normandy, annexed the Cotentin Peninsula from the Breton rulers who were led by the weakened Dukes of Brittany. This placed the mount definitively in Normandy. It is depicted in the Bayeux Tapestry which commemorates the 1066 Norman conquest of England. Harold, Earl of Wessex is pictured on the tapestry rescuing two Norman knights from the quicksand in the tidal flats during a battle with Conan II, Duke of Brittany. Norman Ducal patronage financed the spectacular Norman architecture of the abbey in subsequent centuries.
In 1067, the monastery of Mont Saint-Michel gave its support to duke William of Normandy in his claim to the throne of England. It was rewarded with properties and grounds on the English side of the Channel, including a small island off the southwestern coast of Cornwall which was modeled after the Mount and became a Norman priory named St Michael's Mount of Penzance.
During the Hundred Years' War, the English made repeated assaults on the island, but were unable to seize it due to the abbey's improved fortifications. Les Michelettes – two wrought-iron bombards left by the English in their failed 1423–24 siege of Mont Saint-Michel – are still displayed near the outer defense wall.
When Louis XI of France founded the Order of Saint Michael in 1469, he intended that the abbey church of Mont Saint-Michel be the chapel for the Order, but because of its great distance from Paris, his intention could never be realized.
The wealth and influence of the abbey extended to many daughter foundations, including St Michael's Mount in Cornwall. However, its popularity and prestige as a centre of pilgrimage waned with the Reformation, and by the time of the French Revolution there were scarcely any monks in residence. The abbey was closed and converted into a prison, initially to hold clerical opponents of the republican régime. High-profile political prisoners followed, but by 1836, influential figures – including Victor Hugo – had launched a campaign to restore what was seen as a national architectural treasure. The prison was finally closed in 1863, and the mount was declared a historic monument in 1874. Mont Saint-Michel and its bay were added to the UNESCO list of World Heritage Sites in 1979, and it was listed with criteria such as cultural, historical, and architectural significance, as well as human-created and natural beauty.