Ever wider breaches for new highways make a walk atop the four-mile-long crumbling walls increasingly problematic, but it is possible to drive alongside their entire five-mile length. Badly shaken by the earthquake of 1894, the inner rampart, 12 feet thick and 43 feet high, with 90 towers and seven monumental gates, is still the most imposing Byzantine monument. Begun by Theodosius II in 413, complemented by an outer wall and a moat connecting the Castle of the Seven Towers (Yedikule)—used by the sultans as a state prison for high dignitaries and European ambassadors at the Sea of Marmara with the Golden Horn, these walls, the strongest fortifications of the Middle Ages, were breached only twice—by the Latins in 1204 and the Turks in 1453.
On this itinerary, or any other, a must is the Kariye Museum near the Edirne gate. The church of the Monastery of Chora, dating back to the reign of Theodosius II (408-50), was rebuilt by Justinian after the earthquake of 558. In the 12th century, it was again restored by order of Maria Dukas, a niece of Alexis Comnenus. There are remnants of mosaics belonging to that period, but the superb masterpieces whose fame has spread throughout the world date from the 14th century. Above the front door, you can still make out a kneeling Theodosius, offering Christ a model of the church. The whole story of the beginnings of Christianity is told on these walls, with a careful and even homely realism which brings it closer to western primitive art than to the formal Byzantine images of God in His glory, holy saints, and royal emperors. The Turks only converted the church of the Holy Savior in Chora into the Kariye Mosque under the reign of Bayezit II (1481-1512). (The splendid mosques were saved and restored with the help of the Byzantine Institute of America.)
Higher up, backed against the ramparts are the romantic ruins of the Tekfur Sarayi (so-called palace of Constantine Porphyrogenitus), two storys of large rooms with rounded arches. Further along lie the sad remnants of the once magnificent Blachernae Palace, built by Alexis Comnenus, to which his son Manuel II transferred the imperial court in 1150. The Latin emperors resided there in unwonted luxury, as well as the Palaeologues in ever greater poverty, abandoning wing after wing till the bitter end in 1453, when the palace fell a victim because of its proximity to the walls.