Guernsey is an island in the English Channel off the coast of Normandy that is part of the Bailiwick of Guernsey, a British Crown Dependency. It is the second largest of the Channel Islands, an island group roughly north of Saint-Malo and the Cotentin Peninsula. The jurisdiction consists of ten parishes on the island of Guernsey, three other inhabited islands (Herm, Jethou and Lihou), and many small islets and rocks. It is not part of the United Kingdom, although defence and some aspects of international relations are managed by the UK.

History

Early history

Around 6000 BC, rising seas created the English Channel and separated the Norman promontories that became the bailiwicks of Guernsey and Jersey from continental Europe. Neolithic farmers then settled on its coast and built the dolmens and menhirs found in the islands today, providing evidence of human presence dating back to around 5000 BC.

Evidence of Roman settlements on the island, and the discovery of amphorae from the Herculaneum area and Spain, show evidence of an intricate trading network with regional and long distance trade. Buildings found in La Plaiderie, St Peter Port dating from 100–400 AD appear to be warehouses. The earliest evidence of shipping was the discovery of a wreck of a ship in St Peter Port harbour, which has been named "Asterix". It is thought to be a 3rd-century Roman cargo vessel and was probably at anchor or grounded when a fire broke out. Travelling from the Kingdom of Gwent, Saint Sampson, later the abbot of Dol in Brittany, is credited with the introduction of Christianity to Guernsey.

Middle Ages

In 933, the Cotentin Peninsula including Avranchin which included the islands, were placed by the French King Ranulf under the control of William I. The island of Guernsey and the other Channel Islands represent the last remnants of the medieval Duchy of Normandy. In 1204, when King John lost the continental portion of the Duchy to Philip II of France, the islands remained part of the kingdom of England. The islands were then recognised by the 1259 Treaty of Paris as part of Henry III's territories.

During the Middle Ages, the island was a haven for pirates that would use the "lamping technique" to ground ships close to the island. This intensified during the Hundred Years War, when, starting in 1339, the island was occupied by the Capetians on several occasions. The Guernsey Militia was first mentioned as operational in 1331 and would help defend the island for a further 600 years.

In 1372, the island was invaded by Aragonese mercenaries under the command of Owain Lawgoch (remembered as Yvon de Galles), who was in the pay of the French king. Owain and his dark-haired mercenaries were later absorbed into Guernsey legend as invading fairies from across the sea.

Early modern period

As part of the peace between England and France, Pope Sixtus IV issued in 1483 a Papal bull granting the Privilege of Neutrality, by which the Islands, their harbours and seas, as far as the eye can see, were considered neutral territory. Anyone molesting Islanders would be excommunicated. A Royal Charter in 1548 confirmed the neutrality. The French attempted to invade Jersey a year later in 1549 but were defeated by the militia. The neutrality lasted another century, until William III of England abolished the privilege due to privateering activity against Dutch ships.

In the mid-16th century, the island was influenced by Calvinist reformers from Normandy. During the Marian persecutions, three women, the Guernsey Martyrs, were burned at the stake for their Protestant beliefs, along with the infant son of one of the women. The burning of the infant was ordered by Bailiff Hellier Gosselin, with the advice of priests nearby who said the boy should burn due to having inherited moral stain from his mother. Later on Hellier Gosselin fled the island to escape widespread outrage.

During the English Civil War, Guernsey sided with the Parliamentarians. The allegiance was not total, however; there were a few Royalist uprisings in the southwest of the island, while Castle Cornet was occupied by the Governor, Sir Peter Osborne, and Royalist troops. In December 1651, with full honours of war, Castle Cornet surrendered – the last Royalist outpost anywhere in the British Isles to surrender.

Wars against France and Spain during the 17th and 18th centuries gave Guernsey shipowners and sea captains the opportunity to exploit the island's proximity to mainland Europe by applying for letters of marque and turning their merchantmen into privateers.

By the beginning of the 18th century, Guernsey's residents were starting to settle in North America, in particular founding Guernsey County in Ohio in 1810. The threat of invasion by Napoleon prompted many defensive structures to be built at the end of that century. The early 19th century saw a dramatic increase in the prosperity of the island, due to its success in the global maritime trade, and the rise of the stone industry. Maritime trade suffered a major decline with the move away from sailing craft as materials such as iron and steel were not available on the island.

Le Braye du Valle was a tidal channel that made the northern extremity of Guernsey, Le Clos du Valle, a tidal island. Le Braye du Valle was drained and reclaimed in 1806 by the British Government as a defence measure. The eastern end of the former channel became the town and harbour (from 1820) of St Sampson's, now the second biggest port in Guernsey. The western end of La Braye is now Le Grand Havre. The roadway called "The Bridge" across the end of the harbour at St Sampson's recalls the bridge that formerly linked the two parts of Guernsey at high tide. New roads were built and main roads metalled for ease of use by the military.

Contemporary period

During the First World War, about 3,000 island men served in the British Expeditionary Force. Of these, about 1,000 served in the Royal Guernsey Light Infantry regiment formed from the Royal Guernsey Militia in 1916.

From 30 June 1940, during the Second World War, the Channel Islands were occupied by German troops. Before the occupation, 80% of Guernsey children had been evacuated to England to live with relatives or strangers during the war. Most children returned home after the war ended in 1945. The occupying German forces deported over 1,000 Guernsey residents to camps in southern Germany, notably to the Lager Lindele (Lindele Camp) near Biberach an der Riß and to Oflag VII-C in Laufen. Guernsey was very heavily fortified during World War II, out of all proportion to the island's strategic value. German defences and alterations remain visible, particularly to Castle Cornet and around the northern coast of the island. Guernsey and Jersey were both liberated on 9 May 1945, now celebrated as Liberation Day on the two islands.

During the late 1940s the island repaired the damage caused to its buildings during the occupation. The tomato industry started up again and thrived until the 1970s when the significant increase in world oil prices led to a sharp, terminal decline. Tourism has remained important. Finance businesses grew in the 1970s and expanded in the next two decades and are important employers. Guernsey's constitutional and trading relationships with the United Kingdom is largely unaffected by Brexit although those with France have resulted in increased bureaucracy.