 In 1770 Russian forces under Count Alexei Grigoryevich Orlov besieged Kastro for 60 days during the Russo-Turkish War of 1768–1774.The fortress had just surrendered when an attack by the Ottoman fleet on the Russian vessels in Mudros Bay forced the Russians to withdraw (24 October 1770).Under Ottoman rule, Lemnos initially formed part of the "sanjaks" of Gallipoli or Mytilene under the Eyalet of the Archipelago, but was constituted as a separate "sanjak" in the reforms of the mid-19th century, at the latest by 1846.