A trial of the pyx is mentioned in the Lansdowne MSS.
They are probably of the Norman period, and were kept in the Pyx Chapel at Westminster, now in the custody of the Commissioners of Works.
In the East it was kept against the wall behind the altar; in the West, in a locked aumbry in some part of the church, or (as in England and France) in a pyx made in the form of a dove and suspended over the altar.
This chest was formerly kept in the Chapel of the Pyx in Westminster Abbey.
The chapel or chamber of the Pyx is part of the undercroft of the original dormitory, and is early Norman work of the Confessor's time.
It was used as a treasury for the regalia and other articles of value in early times, and here were kept the standard coins of the realm used in the trial of the pyx now carried out at the Mint.
The social work of the Church was transferred to others, and little by little the deacons sank in importance until at last they came to be regarded merely as subordinate officers of public worship, a position which they hold in the Roman Church to-day, where their duties are confined to such acts as the following: - censing the officiating priest and the choir, laying the corporal on the altar, handing the paten or cup to the priest, receiving from him the pyx and giving it to the subdeacon, putting the mitre on the archbishop's head (when he is present) and laying his pall upon the altar.
It contains many interesting sculptures and paintings, besides one especially fine silver pyx, the work of Juan de Arphe, dating from 1571.