The Benedictine Abbey was founded in the 9th Century by the King of Brittany called Nominoe and the castle was built in the 12th Century on the feudal mound dominating the bridge.
The old bridge of Lehon was originally a toll crossing of the river – the toll producing revenue for the abbey. It was a strong fortification point between the banks of Lehon and Lanvally.
The old castle has been besieged in history by Henry II of England who razed it to the ground. Many battles have been fought between the English and the French – the English helping in a battle for the Dukedom of Brittany between two contendors (see history at Fort la Latte).
A very popular mayor of Lehon – Louis Chupin – lived at Val Rive in the second half of the 19th Century, and named the impressive house Maison Chupin. He owned a textile factory employing local workers and also purchased a tannery at the edge of his property. He was instrumental in campaigning to obtain funds for the restoration of the abbey.