Constantinople, 10th–12th Centuries
For the God-ordained Christian Roman Empire forged at the Council of Nicaea, Emperor Constantine I dedicated a new capital city in 330. Erected on the site of the ancient Greek colonial port of Byzantium, New Rome, or Constantinople (Konstantinopolis, or City of Constantine, in Greek) was located on an easily defended triangular bit of land on the European shore of the Bosphorus Strait. Directly to its north was the crescent-shaped mouth of a small river emptying into the Bosphorus, known as the Golden Horn, which formed the only natural harbor in the area. To its south stretched the Sea of Marmara, which emptied into the Mediterranean through the Dardanelles Strait. The Bosphorus-Marmara-Dardanelles seaway separated Europe from the West Asian landmass and linked the interior of Eurasia beyond the Black Sea directly to the Mediterranean. Byzantium, with its sea walls and the Golden Horn, dominated traffic on this crucial seaway. Moreover, the city was located on the most direct overland pathway between the two continents. Through fortifications of this land triangle, Constantinople was transformed into an impregnable fortress-city that controlled all the important lines of communication between the European and Asian worlds.