This is the 9686th most frequent French word.
emmurés
"Emmurés" means "walled in" or "entombed."
In this sentence, 'emmurés' is used in a figurative sense to describe the treasures being enclosed or sealed behind walls.
Les trésors anciens étaient emmurés dans une chambre secrète.
The ancient treasures were walled up in a secret chamber.
Here, 'emmurés' is applied literally to describe being physically enclosed by walls, such as in a prison cell.
Les prisonniers ont vécu des années emmurés dans une cellule sombre.
The prisoners lived for years walled up in a dark cell.
In this instance, 'emmurés' is used metaphorically to signify burying or hiding emotions within oneself.