Passage: The German naval command decided that because Roon and the other armored cruisers of the III Scouting Group were slow and lacked thick enough armor, they were unsuitable for service in the North Sea where they would risk contact with the powerful British Grand Fleet. Therefore, on 15 April 1915, Roon and the rest of III Scouting Group were transferred to the Baltic, where they would face the significantly weaker Russian Baltic Fleet. The unit was dissolved and Roon and the other vessels were assigned to the Reconnaissance Forces of the Baltic, under the command of KAdm Albert Hopman. At the same time, FK Hans Gygas replaced Karpf, who in turn became the deputy commander of the unit and made Roon his flagship. On 30 April, the ship went into drydock in Kiel for an overhaul, returning to service for the attack on Libau on 7 May. On 11 May, the British submarine E9 spotted Roon and several other ships en route to Libau, which had been recently captured by the German army. E9 fired five torpedoes at the German flotilla; two passed closely astern of Roon while the other three missed their targets as well. Roon thereafter took part in a series of sorties into the central Baltic as far north as Gotska Sandön on 13–16 May, 23–26 May, 2–6 June, 11–13 June, and 20–22 June.Karpf transferred to the light cruiser Lübeck while Hopman relocated to Roon while his flagship, the armored cruiser Prinz Adalbert, was under repairs for a torpedo hit to cover a minelaying operation with Albatross on 30 June that lasted through 2 July and resulted in the Battle of Åland Islands. The light cruiser Augsburg and three destroyers were escorting the minelaying cruiser SMS Albatross when they were attacked by four Russian cruisers—the armored cruisers Bayan, Admiral Makarov, and light cruisers Bogatyr and Oleg. Augsburg escaped while the destroyers covered the retreat of the Albatross, which was severely damaged and forced to seek refuge in neutral Swedish waters. Roon joined Lübeck to relieve the beleaguered German destroyers. Upon...

Question: When did Germans attack the Soviets at Zerel?
10 August