Nothing definite is known of Brest before about 1240, when a count of Léon ceded it to John I, Duke of Brittany. In 1342, John IV, Duke of Brittany, surrendered Brest to the English, in whose possession it was to remain until 1397. The importance of Brest in medieval times was great enough to give rise to the saying, "He is not the Duke of Brittany who is not the Lord of Brest". With the marriage of Francis I of France to Claude, the daughter of Anne of Brittany, the definitive overlordship of Brest – together with the rest of the duchy – passed to the French crown.
The advantages of Brest's situation as a seaport town were first recognized by Cardinal Richelieu, who in 1631 constructed a harbor with wooden wharves. This soon became a base for the French Navy. Jean-Baptiste Colbert, finance minister under Louis XIV, rebuilt the wharves in masonry and otherwise improved the harbour. Fortifications by Vauban (1633–1707) followed in 1680–1688. These fortifications, and with them the naval importance of the town, were to continue to develop throughout the 18th century.
In 1694, an English squadron under Lord Berkeley, was soundly defeated in its attack on Brest.
In 1917, during the First World War, Brest was used as the disembarking port for many of the troops coming from the United States. Thousands of such men came through the port on their way to the front lines.
In the Second World War, the Germans maintained a large U-boat submarine base at Brest. In 1944, after the Allied invasion of Normandy, the city was almost totally destroyed during the Battle for Brest, with only a tiny number of buildings left standing. After the war, the West German government paid several billion deutsche marks in reparations to the homeless and destitute civilians of Brest in compensation for the destruction of their city. Large parts of today's rebuilt city consist of utilitariangranite and concrete buildings. The French naval base now houses the
