The Theodosian walls of Constantinople. For 1000 years the walls made the city almost impregnable. They resisted the Mongols, the Bulgars, the Seljuks and other invading armies. Only twice were they breached. The Second Crusade, in one of the greatest crimes of the ancient world, scaled the walls of their supposed allied using the the masts of their ships. The orgy of looting and killing by the despicable French and Venetians combined with their incompetent administration economically broke financial back of the Byzantine empire and it was never the same. The Greeks were able to throw the Latins out 80 years later leading to the second flowering of Byzantium. Many of the greatest treaures of Venice were stolen from Byzantium including the four horses statue and the doors of St. Mark to name a few. The second breach of the walls was fatal. The Sultan Mehmet II beseiged the city for three months. The Greeks, ably led by Constantine VI, were able to hold out for three months against an army that outnumbered them 300,000 to 14,000. In the end, the relentless pounding of the walls by the world's largest cannon at the time, the intelligence and sheer relentlessness of an increasingly desparate Sultan and the cowardice of a Genoan contingent who fled the city leaving a door unguarded led to the fall of the city. While most of the city was slaughtered, Mehmet did not raze the city. Instead, he made it his capital. Istanbul comes from Stamboul, an old Greek name applied to the city.