The fourth group consists of the buildings erected during or since the
Renaissance (_i.e._ revival) period, and is marked by a return to the
styles of past ages or distant countries for the architectural
features and ornaments of buildings; and by that luxury, complexity,
and ostentation which, with other qualities, are well comprehended
under the epithet Modern. This group of buildings forms what is known
as Renaissance architecture, and extends from the epoch of the revival
of letters in the fifteenth century, to the present day.

The first two of these styles--namely, the architecture of the beam,
and that of the round arch--are treated of in this little volume. They
occupy those remote times of pagan civilisation which may be
conveniently included under the broad term Ancient; and the better
known work of the Greeks and Romans--the classic nations--and they
extend over the time of the establishment of Christianity down to the
close of that dreary period not incorrectly termed the Dark ages.
Ancient, Classic, and early Christian architecture is accordingly an
appropriate title for the main subjects of this volume, though, for
the sake of convenience, some notices of Oriental architecture have
been added. Gothic and Renaissance architecture form the subjects of
the companion volume.

It may excite surprise that what appears to be so small a difference
as that which exists between a beam, a round arch, or a pointed arch,
should be employed in order to distinguish three of the four great
divisions. But in reality this is no pedantic or arbitrary grouping.
The mode in which spaces or openings are covered lies at the root of
most of the essential differences between styles of architecture, and
the distinction thus drawn is one of a real, not of a fanciful nature.

Every building when reduced to its elements, as will be done in both
these volumes, may be considered as made up of its (1) floor or plan,
(2) walls, (3) roof, (4) openings, (5) columns, and (6) ornaments, and
as marked by its distinctive (7) character, and the student must be
prepared to find that the openings are by no means the least important
of these elements. In fact, the moment the method of covering openings
was changed, it would be easy to show, did space permit, that all the
other elements, except the ornaments, were directly affected by the
change, and the ornaments indirectly; and we thus find such a
correspondence between this index feature and th