The chapel was built on the remains of a site occupied since Roman times. In 1125, the estate of Castennec was detached from the parish of Bieuzy and granted by Alain I of Rohan to the Abbey of Redon. The original church, still mentioned in records dating from 1380, was later destroyed.

A second chapel was erected towards the end of the fifteenth century under the joint patronage of the Rohan and Rimaison families. Their combined coats of arms can be seen on the chapel’s exterior wall, while the arms of the Rimaison family alone appear on one of the carved roof timbers.

The bell tower was rebuilt in the nineteenth century.