German battleship Tirpitz and 4 destroyers departed Trondheim, Norway to intercept Allied convoys PQ-12 and QP-8, which departed from Reykjavik in Iceland for Murmansk in Russia and from Murmansk in Russia for Hvalfjör_ur in Iceland, respectively. The British Royal Navy learned of this departure via Ultra decryption and dispatched a fleet centered around battleships HMS Duke of York, HMS King George V, and HMS Renown to attack.