By building walls across the land between the Golden Horn and the sea at distances farther and farther from Seraglio Point, the city has been successively enlarged; the great land walls, within which the shrunken city now lies, are mainly the work of Theodosius II. These, the walls of the Constantinople known to the Crusaders, are still comparatively perfect; a triple line on the land side and a single line around the sea margin, some fourteen miles of walls, eight or ten to fifteen feet thick, strengthened by great towers, completely girdles the city round about. The land-wall of Constantine’s city, situated between the Acropolis and the present walls, has disappeared, but its course has been traced (see Fig. 1). _Acropolis._--The topography of ancient Constantinople has engaged the attention of generations of writers, and an approximation to true results has undoubtedly been reached. First we must mention Pierre Gilles, usually called Gyllius, who, travelling to collect MSS. for Francis I., resided in the city for many years, and died in 1555. Then Du Cange, in his great work _Constantinopolis Christiana_, 1680, by a careful comparison of the authorities, certainly made discoveries in a country he had never visited. The folios of Banduri[11] followed in 1711; and in 1861 Labarte published a more detailed study of the Imperial quarter, chiefly based on the ample notices in the Book of Ceremonies of Constantine Porphyrogenitus. This work, _Le Palais Impérial de Constantinople et ses Abords_, shows remarkable insight and critical acumen. Buzantios in _Constantinopolis_, 1861, and Paspates in his _Byzantinae Melatae_, 1877, made several further identifications. The latter followed with _The Great Palace of Constantinople_, recently translated by Mr. Metcalfe, which goes over the same ground as Labarte; but the excavations for the railway, which now circles Seraglio Point, had in the meantime exposed some remains, and made the examination of certain walls possible. Although Paspates made several valuable suggestions, many of his conclusions are certainly not sustained by his reasoning; indeed, Labarte in many points of divergence was probably much nearer the facts. Paspates’ views were accepted by Mr. Bury,[12] to be followed in turn by Mr. Oman in _The Byzantine Empire_ of the “Story of the Nations” Series. A work in Russian has recently been devoted to the study of the Palace quarter.[13] Unger’s collection of topographical references in _Quellen der Byzantinischen Kunstgeschichte_ is also of the greatest service. [Illustration: FIG. 1.--Plan of Constantinople showing its development.] In 1892 appeared Dr. Mordtmann’s _Esquisse_, together with a large plan of the city, on which the probable identifications of the ways and buildings were laid down; this was prepared at the instance of the Comte Riant, who, in his _Exuviae Constantinopolitanae_, contributed the result of much research to our knowledge of Byzantine antiquities.