The Manche area was inhabited from the Palaeolithic era on. After the Celts came the Gauls, the Romans, the Saxons, the Franks and the Scandinavians.

The mysterious town of Coriallo in "The Antonine Itinerary" was probably located within the Cherbourg metropolitan district, in the Mielles area on the right bank of the Divette.

At the end of the 4^th century, the presence of a castrum (fortified camp) is noted on the left bank of the Divette. From that point on, the site will be continuously occupied as is proved by the archaeological digs carried out from 1978 to 1981 on the castle site. The date of the latter's construction on the castrum foundations is not known.

The name of Cherbourg appears for the first time in 1026 in the deed of donation of the castle by the Duke Richard II to his future wife.

In 1053, Duke William came to Cherbourg with his wife Matilda and founded a canons' monastery in accordance with a vow.

The Anglo-Norman state created in 1066 after William's victory at Hastings was a decisive factor in the development of Cherbourg with its exceptional geographic position in the heart of this state.

In 1145, William the Conqueror's granddaughter, Matilda, acquired land in the parish of Equeurdreville (La Croûte du Homet) on the approximate site of the modern Cherbourg Arsenal. She ordered the construction of an abbey dedicated to the Holy Virgin, whose cult was in full expansion at the time, the Abbaye du Voeu, of which important remains still stand.

The Anglo-Norman State - or Plantagenet State - was then at its peak and occupied a large part of Western Europe, from Scotland to the Pyrenees.

In 1204, the King of France, Philip-Auguste, making the most of feudal legal quibbles, took control of Normandy. Franco-English relations deteriorated towards the end of the 13^th century. The English carried out a raid on Cherbourg, sacking the Abbaye du Voeu, the first in a long series of depredations, and set fire to the town. Only the castle held firm.

Towards 1300, King Philippe IV le Bel had fortifications built. They would subsequently be rebuilt and consolidated several times, thus making Cherbourg impregnable.

In 1337, the Hundred Years War began. Cherbourg became a strategic trump card. During the conflict, the town changed sovereign six times. In 1354, the King of France offered it to his future son-in-law, Charles de Navarre, who ceded it to the English in 1378. In 1394, the son of Charles de Navarre took back the town and exchanged it with the King of France for the Comté of Nemours. Then, in 1418, Cherbourg had to surrender to the English and didn't become French again until 1450, following a financial agreement.

Little by little, the town lost the importance that it had acquired during the Franco-English conflict.

The end of the 16^th century saw the outbreak of the Wars of Religion. In 1563 and in 1574, the Protestants of Normandy, with the Count of Montgomery at their head, tried to capture Cherbourg but the town was victoriously defended by Jacques de Matignon whose descendants subsequently governed Cherbourg until the middle of the 18^th century.

In 1686, at the request of Louis XIV, Vauban came to Cherbourg. He noted that the town was vulnerable only from its seaward side and suggested important defence works that were undertaken in 1688. However, the following year, Louvois, the War Minister, decided to suspend the work. He ordered the demolition of the castle and the fortifications that were falling into disrepair: Cherbourg was no longer a stronghold.

At that time, the harbour consisted solely of a lagoon with a stable bottom where forty vessels could anchor but there was no protection for this natural harbour as shown by the aftermath of the battle known as the La Hougue in 1692.

From 1739 to 1744, on the orders of Louis XV, the town was given a commercial port that, in 1758, in the course of another Anglo-French conflict, was entirely destroyed. It didn't open to traffic again until 1789.