too, were great glass-makers. So glass-making came down through
the ages. The Byzantine churches usually were lighted by a row of tiny
glass windows round the base of the dome. Some of this ancient glass
still remains in St. Sofia. The common way of making such windows was
to cut a design in a slab of marble or plaster, and then insert small
pieces of colored glass. Sometimes, too, a pattern for wall decoration
was worked out by sticking fragments of glass into soft stucco. So the
first mosaic work began. We can see some of it in the museums of
England."

"There seems to be a great deal to see in those London museums, Uncle
Bob," Jean gasped.

"I am afraid you will be more convinced of that fact than ever when you
get there," chuckled Uncle Bob. "But to return to Giusippe's mosaics.
You may remember, perhaps, that when the Mohammedans invaded
Constantinople and found how important a part the glass-makers played
in decorating the churches, they at once handed the artisans over to
the caliphs, that they might be set to work adorning their mosques. Now
the Mohammedans believed it a crime to make a copy of either man or
woman in a picture, a carving, or a statue. It was punishable to pay
reverence to sacred figures; therefore all decoration in their churches
took the form of flowers, fruit, or conventional designs. So no great
mosaic pictures with figures such as these were made. Between the
thirteenth and fourteenth centuries Damascus became the center of
glass-making, and there are in existence in some of the museums old
Arab lamps which hung in the mosques with inscriptions from the Koran
engraved upon them. It is Giusippe's St. Mark's which revived the art
of mosaic making, and served as the bridge between those Pagan days and
the days when with Christianity the arts revived and mosaic makers
began to represent in glass figures of Christ and the saints."

"And then the painters came, as Giusippe has said," put in Jean.

"Yes, the great artists were born, and from that time pictures on
canvas instead of pictures of glass decorated the churches. But the
mosaic makers did an important service to art, for it was they who
indirectly gave to the world the idea of making stained-glass windows.
And in Venice those who ceased to make mosaics made instead the
beautiful Venetian glass of which Giusippe has told us."

"And are there no mosaics made now, Uncle Bob?" asked Jean.

"Yes. When in 1858 it became necessary to restor