It was the Germans' intention to destroy the Russian Army and occupy the West Estonian Archipelago (Moonsund Archipelago). The Germans captured the archipelago, with its main islands of Saaremaa (Ösel), Hiiumaa (Dagö), and Muhu (Moon) during the Operation Albion in September 1917. This left a Russian squadron consisting of the old Russo-Japanese War-era pre-dreadnought battleships Tsesarevich, and Slava, together with cruisers and destroyers, stranded in the Gulf of Riga. The Russian fleet escaped on 17 October 1917 by way of the Suur Strait separating the island of Muhu from the Estonian mainland.