uring many centuries the architects struggled with this problem of
constructing a building that was large enough. The Roman tradition
taught them how to build heavy stone walls with very small windows lest
the walls lose their strength. On the top of this they then placed a
heavy stone roof. But in the twelfth century, after the beginning of
the Crusades, when the architects had seen the pointed arches of the
Mohammedan builders, the western builders discovered a new style which
gave them their first chance to make the sort of building which those
days of an intense religious life demanded. And then they developed this
strange style upon which the Italians bestowed the contemptuous name of
"Gothic" or barbaric. They achieved their purpose by inventing a vaulted
roof which was supported by "ribs." But such a roof, if it became too
heavy, was apt to break the walls, just as a man of three hundred pounds
sitting down upon a child's chair will force it to collapse. To overcome
this difficulty, certain French architects then began to re-enforce the
walls with "buttresses" which were merely heavy masses of stone against
which the walls could lean while they supported the roof. And to assure
the further safety of the roof they supported the ribs of the roof by
so-called "flying buttresses," a very simple method of construction
which you will understand at once when you look at our picture.

This new method of construction allowed the introduction of enormous
windows. In the twelfth century, glass was still an expensive curiosity,
and very few private buildings possessed glass windows. Even the castles
of the nobles were without protection and this accounts for the eternal
drafts and explains why people of that day wore furs in-doors as well as
out.

Fortunately, the art of making coloured glass, with which the ancient
people of the Mediterranean had been familiar, had not been entirely
lost. There was a revival of stained glass-making and soon the windows
of the Gothic churches told the stories of the Holy Book in little
bits of brilliantly coloured window-pane, which were caught in a long
framework of lead.

Behold, therefore, the new and glorious house of God, filled with an
eager multitude, "living" its religion as no people have ever done
either before or since! Nothing is considered too good or too costly or
too wondrous for this House of God and Home of Man. The sculptors, who
since the destruction of the Roman Empire