" This is a calamitous story, but it contains a moral for our own time: western civilisation and culture are more likely to collapse from internal dissension than from external pressure. The enemy is within. It is a hydra with many heads, but three predominate—Stupidity, Envy and Greed. The destruction of Constantinople and its Empire is an appalling example of what can result from political opportunism and narrow patriotism. It is not necessary to look very far in the western world at this moment to see similar dangers arising from similar misguided policies. "

― Ernle Bradford , The Great Betrayal: The Great Siege of Constantinople