The naval Battle of the Bismarck Sea in March 1943 was fought over the Japanese attempt to reinforce Lae with troops sent by sea from Rabaul, an attempt foiled by sustained Allied attack on the Japanese troop transports. In mid-1943, after defeats in the Kokoda Track campaign, the Battle of Buna–Gona and the Battle of Wau, the Japanese retreated to Lae and Salamaua. However, the Salamaua–Lae campaign involved many weeks of fierce fighting, before the town fell to the Allies on 16 September.