Now, the history of this concurrence of art with construction is the History of Architecture; and, to an architectural historian who is capable of taking at once an artistic, a philosophical, a political, and a religious view of the facts which he chronicles, nothing can be more interesting than to follow out from the earliest ages to which we can carry back our researches, firstly, the practical changes in building, arising from the exigencies of climate, the stage of civilisation, the traditions of race, and the varied influences of political and religious circumstances; and to connect with these the changes, the progress, and perhaps the decline and degradation of the art made use of in the decoration of their buildings; and to trace out the causes which led to these changes. Let us not, however, suppose that a knowledge, however intimate or accurate, of architectural history, is of necessity a part of the study of architecture itself. On the contrary, at no period when a genuine, unborrowed style of architecture has prevailed, has any knowledge whatever existed of the history of art; nor at any period previous to our own has the history of architecture--beyond a very limited knowledge of that of Greece and Rome--been viewed as an object of study. From the dawn of civilisation to what is known as “the revival of letters,” the leading nations of the world possessed each a genuine architecture of their own; all growing, by a natural growth, from an original stem--unborrowed and unimitated--and practised by artists highly skilled in their art, but ignorant of its history. The “revival of letters” was followed by a revival also of the architecture of those races whose literature was resuscitated; and with this revival came a certain, though scanty, knowledge of its history; but the investigation of the entire history of architectural art, and the constituting it into a branch of our literature, has been reserved for a period which possesses no architectural style of its own, excepting as the result of revival or imitation.