The département’s name comes from Mor and Bihan, the Breton words for "sea" and "little" respectively, in reference to the miniature inland sea.
The Veneti tribe was conquered by Julius Caesar in 56 BC. Vestiges of the Roman occupation can still be found in the many megalithic sites that litter the county.
The Bretons, originally from what is now Great Britain, fled the Angles and Saxons to settle on the continent circa 800 AD and in 845 Nominoë, Count of Vannes, wrested Brittany’s independence from the Franks. After Alain Barbe-Torte’s defeat of the Normans in 939, Le Broerec came into the fold of the Duchy of Brittany.
After the death and defeat in 1364 of Charles de Blois, one of the pretenders to the crown, his rival Jean de Montfort became Duke of Brittany. His illustrious line was to continue until Anne of Brittany (1488-1514).
In 1532, the states of the Duchy of Brittany, namely Vannes, Ploërmel, Auray and Hennebont, voted the incorporation of Brittany into France. The department gradually improved its infrastructure, developing road and railway networks.
Morbihan has since become a tourist hotspot and favoured location for holiday houses.