Grammata of a black satin half-embroidered vestment

Grammata in black silk satin embroidered with gold color silk thread belonging to a church vestment commissioned in Italy by King João V to the Royal Basilica of Mafra.
The grammata is a piece of square format, as the name says, that was placed attached to the alb, at the end of the chasuble. Its use was reserved to Pontifical masses. This piece has fallen into disuse.