THE RELIEFS OF THE MAIN ALTAR OF SAN MARTIN

SUPPORT AND ELABORATION 

The relief of the Mass of Saint Gregory is made up of at least two large wood panels glued and nailed together to which another piece was added to give greater volume. The back has not been hollowed out and we can see marks left by adzes and gouges.   

On the altarpiece's predella on which this and the relief depicting Saint James (Santiago) are to be found, the poligonally-shaped niches have sides and rears whose panels were  joined together using butt joints whose seams contain ramie or tow (in a similar fashion to the painted panels and niches along the first and second main horizontal sections). They were then attached directly to the bottom and upper sections by either dovetail joints or nails. Decoration of rear windows was carved directly onto the surface of the panels forming the walls of the niches themselves.  

Judging by their style and concept, the niches on the predella might well have come from an earlier altarpiece, as pointed out by Arias Martínez and Hernández Redondo, since their construction appears to diverge from common Flemish practice.

The Calvary is made up of six rounded, independent figures.