What is a Pyx?
In the Christian religion, a pyx is for holding the consecrated as well as the unconsecrated bread, for the Eucharist or communion, which commemorates the death of Jesus Christ.
The simplest form is that of the cylindrical wafer caskets, with flat or arching cover, of metal or ivory, some few of which have come down from Christian antiquity.
In the second half of the Middle Ages the pyx was much elaborated; resting upon a cup-like base, it copied the structural plan of a tower (turris; turriculum).
In the later Middle Ages this development reached its culmination in the stone or metal tabernacle erected at the north end of the choir, on the wafer side of the altar, being sometimes executed with admirable artistic skill; its structural pattern was the Gothic tower.
This development was anticipated in the eucharistic shrines of earlier ages. The consecrated element was enclosed in a compartment of lattice-work. Today, the pyx is most often used for transporting the communion wafers to the bedside of a sick believer or other offsite location.
During that stage of its development when processions and public display of the Host became prominent, the festival of Corpus Christi led to the construction and use of a vessel that should at once augustly and visibly present the blessed sacrament to the eye. Thus the monstrance came into being (monstrantia, ostensorium, eustodia, tabernaculum).
There was, however, no need of a new invention, and the makers confined themselves to copying the transparent reliquaries and ciboria, which were already at hand, being occasioned by quite a similar purpose. For the base the Gothic chalice was imitated in the diversity of its standard forms.
Its knob (nodes) likewise recurs, but with a greater tendency toward sumptuous elaboration. Upon the like support there mounts an artistic superstructure, designed like the transept of a church, having three to five naves. The free plane surfaces are of both simpler and richer disposition. To crown all, there are one or more turrets (hence the designation turricula). The effect of richness is enhanced by settings of pearls and precious stones.
The Greek liturgy prescribes the presentation of the elements mingled in the chalice, for which purpose there was in use, from quite early times, a metal spoon (labis, labida), the Holy the handle of which ends in a cross. The Western Church inventories and donation records of the same time frequently mention spoons (cochlearia), which may have served partly for mixing water and wine, partly in administering to the poor, being still in use for that purpose in Spain.