Fort la Latte, or the Castle of the Rock Goyon (French: La Roche-Goyon, Breton: Roc'h-Goueon), is a castle in the northeast of Brittany in the commune of Plévenon, Côtes-d'Armor. It is a famous tourist attraction of the bay of Saint-Malo and the Emerald Coast (France) Côte d'Émeraude. This impressive castle was built on a small piece of land at the Bay of the Fresnay in the 14th century. The castle was built in the 14th century by the Lord of Matignon, Etienne III Gouÿon. The construction of the castle began in the 1340s, its keep dates from the years 1365–1370. In 1379, following the return from exile of the Duke of Brittany Jean IV, the castle was besieged by Bertrand Du Guesclin. The castle was attacked and taken a second time during the Wars of Religion in the sixteenth century, this defeat marking a time of abandonment of the building. It was not until the 18th century, under Louis XIV, that the castle resumed its strategic interest and was bastioned. It was in service until the end of the First Empire when the evolution of military techniques led to its unsuitability. From 1892, it was sold to various private owners before being bought by the historian Frédéric Joüon Des Longrais in 1931 who, having a lifelong passion for archeology, undertook heavy restoration work which took more than twenty years. Electricity only arrived at the castle in 2015.