DVD. Global Treasures. 10 Minutes. Suur, for thousands of years the mighty tower-flanked Istanbul Land Wall was vital for both the defence and further development of the city. The Byzantine emperor, Theodosius The Second, ordered the construction of a new and mighty fortification in 408 A.D. The fortress was built during the reign of Sultan Mehmet Fatih The Second. It was an architectural symbol of the defeat of Constantinople when following more than a thousand years of resistance the inhabitants of the city were forced to surrender to the Osmanic conquerors. The city's most influential dignitaries were imprisoned in the fortress and many perished within its walls. Even the region's sultans were executed there. The fall of the Byzantine Empire created a new flowering period in the city and today Istanbul's famous wall reaches from the Marmara Sea to the Golden Horn, the very long and narrow tributary of the Bosporus.