Grouped inside the walls of the arch are the Church, the Charnel House (or Ossuary) and the Calvary. Charnel Houses existed due to the tiny size of Breton cemeteries (land being more valuable as planted fields) which necessitated disinterring long buried bodies so that newly deceased parishioners could be buried. The bones were placed In the Ossuary with separate skull caskets.

The Calvary comes from the name of the hill where Christ was crucified. Breton Calvaries are small to large granite monuments representing scenes from the Passion and the Crucifixion. They served to help teach religion in the parishes where literacy was not common.

Calvaries should not be confused with the many wayside crosses erected throughout Brittany. These crosses usually mark the site of a procession or part of the pilgrimage route (Tro Breiz) between the seven cathedrals of Brittany