A disc of this description, pierced to receive glass cups, is apparently an earlier form than the well-known corona, the _polycandela_, so long in use in Christian churches. The hanging disc, like so many things Roman and Byzantine, would seem to have survived among the Saracens; something like it may still be found in old Arab houses in Cairo. Elsewhere Paul, speaking of the single lights in St. Sophia, describes them as silver vessels, _like a balance-pan_—in the centre of each rests a cup of ‘well burning oil.’ This passage, I think, throws some light on certain ‘balance-pan’ dishes of rock crystal and glass, preserved in St. Mark’s treasury at Venice (see below, p. 101). Footnote 68: Its relation to the Queen of Sheba we may dismiss. The other two uses that have been assigned to this bowl may be reconciled, if we accept one of the earliest forms of the tradition of the Holy Graal. (I follow here the account given by the late Mr. Thomas Arnold in an article by him in the _Encyclopædia Britannica_.) According to this tradition, Joseph of Arimathea, at the time of the Crucifixion, proceeded first to the upper room where the Last Supper had been celebrated and found there the shallow bowl that had held the Paschal Lamb. Taking this vessel with him, and returning to the scene of the Crucifixion, he received in it drops of blood from the side of our Lord. The double service of the bowl is the essence of this tradition. Mr. Arnold, _à propos_ of the traditionary connection of the Holy Graal with Glastonbury, quotes from Malmesbury a statement that in his day an altar called ‘sapphirus,’ which had been brought from Palestine to St. Davids, had been re-discovered. This may well have been a slab of glass similar to that still preserved at Reichenau. I have been unable to find any further reference to this ‘sapphirus’ altar. Footnote 69: _Il Tesoro di San Marco illustrato da Antonio Passini, Canonico della Marciana._ Published by Ferd. Ongania, Venice, 1886. As in both the text and the plates of this work the glass is mixed up with objects of rock crystal and other materials, I give a reference to the plates on which vessels of glass are reproduced. Footnote 70: This dish should probably rather find a place among the hanging lamps of the next section. There are others of these so-called chalices and patens of which the original use is very problematical. Footnote 71: This vase has been classed by Von Czihak with the so-called Hedwig glasses (see below, p. 115); the resemblance, however, to the German glasses is small. Footnote 72: Note in this connection the inscription on the mounting of the lamp of carved glass (IV. 1 in our list) in St. Mark’s treasury, referring to a bishop of Iberia, the modern Georgia. Not until the reign of Justinian was the Roman empire extended to the east coast of the Euxine—to Lazica and Colchis. Footnote 73: