“ Strategically the Dardanelles is a point of great importance, since it commands the approach to Constantinople from the Mediterranean. The passage of the strait is easily defended, but in 1807 the English admiral (Sir) J. T. Duckworth made his way past all the fortresses into the Sea of Marmora. The treaty of July 1841, confirmed by the Paris peace of 1856, prescribed that no foreign ship of war might enter the strait except by Turkish permission, and even merchant vessels are only allowed to pass the castle of Chanak-Kalehsi during the day. ”