La Roche Goyon takes its name from one of the oldest Breton families (called Gwion, Goion, Gouëon, Goyon and Gouyon).

A legend testifies that a first castle was built by a Goyon under Alain Barbe-Torte in 937.

The current castle, as for him, was started before the appearance of the canon in Brittany (1364) then continued at the option of the good fortune of Goyon in the second half of XIVème century. It existed in 1379 since Du Guesclin sent a detachment to La Roche Goyon who resisted valiantly. The fortress was confiscated for the benefit of Charles V, then returned to its owner by the Treaty of Guérande (1381).

During the fifteenth century, the social rise of the Goyon continued. They appear in the States of Brittany. A Goyon, chamberlain of the duke of Brittany, will marry the heiress of the barony of Thorigni-sur-Vire. The Goyon family leaves the Breton cradle and goes to the history of France. The castle then receives a governor who lodges in a house arranged for this purpose. At the time of the meeting of Brittany with France (realized during the treaty of 1532), it undergoes a new seat (1490), English this time, without success for the invaders.

The coup de grace was carried by the League. Jaques II Goyon, lord of Matignon, Marshal of France, Governor of Normandy and Guyenne, had sided with Henri IV. In retaliation, in 1597, a delegate of the Duke of Mercoeur named Saint-Laurent, besieged and assaulted him. The castle already called at that time La Latte, was dismantled, looted, ravaged, burned. Only the dungeon resisted.

It was at a castle in ruins that Sir Garengeau was interested in fortifying the coast for the defense of Saint-Malo. The castle was transformed accordingly with the agreement of Matignon between 1690 and 1715. It owes much of the aspect we know him.

In 1715, James Ill Stuart came and took refuge there and found the place sinister ... It is true that there failed a nasty evening of November. The same year Louise-Hippolyte GrimaIdi (Princess of Monaco) married Jacques-François-Léonor Gouyon, lord of Matignon, become Duke of Valentinois, provided to take the name and weapons of the Grimaldi without joining his family.

In 1793, the furnace was built to blush the balls and a few counterrevolutionary suspects were imprisoned.

Young MaIouins took it by storm, without success, during the Hundred Days (1815). This was his last warrior episode.

During the nineteenth century, he was gradually abandoned, he had only one guardian. Decommissioned by the War Ministry in 1890, it was sold by the Domains in 1892. It was largely in ruins when it was classified a Historic Monument in 1925. It has been restored since 1931 by the Joüon family of Longrais and is open to the visit . It became the most visited castle in Brittany, after that of the dukes in Nantes.