It was founded in the 6th century by Saint Mewan (known in French as Méen), after whom it was eventually named.

The original foundation had fallen into disuse by the end of the 8th century.

[1] It briefly housed the remains of Saint Petroc after a thief gave them to the abbey in 1177.

In the 17th century it passed through the hands of the Maurists, the Oratorians and the Lazarists.

After 1790, the buildings housed the gendarmerie, a barracks, a school, a minor seminary, a prison and a refugee shelter.