Simpson and his donkey became famous for helping wounded Allied soldiers during the ANZAC campaign at Gallipoli during World War I (1914-1918). In April 1915, the Allies landed troops on the Gallipoli Peninsula on the west shore of the Dardanelles, then controlled by the Ottoman Empire. ANZAC troops, a force of Australian and New Zealand volunteers, played a key role in the landing. If successful, the attack would have opened a route to the Black Sea. The Allied forces, especially the ANZAC's, fought bravely. But they suffered heavy casualties, and Allied commanders ordered them to withdraw in December 1915. The campaign failed disastrously.