The German fleet sortied in the early hours of 31 May, intending to make a demonstration with Hipper's battlecruisers to draw out his British counterparts of the Battle Cruiser Fleet. The British, aware of Scheer's plans, were already at sea, having left their base at Scapa Flow late on 30 May. The four "Nassau"s and the rest of I Battle Squadron formed the center of the German line of battle, astern of "KAdm" Paul Behncke's III Battle Squadron and ahead of the old pre-dreadnoughts of "KAdm" Franz Mauve's II Battle Squadron. "Posen" served as the flagship of II Division under "KAdm" Walter Engelhardt. The initial phase of the action, which began at 16:00 on 31 May, consisted of a running battle between the opposing battlecruiser squadrons as Hipper lured the British commander, Vice Admiral David Beatty, south toward Scheer's fleet. Upon spotting the German fleet, Beatty turned north, leading the Germans toward the approaching Grand Fleet under Admiral John Jellicoe.