In 1915, Australian and New Zealand soldiers formed part of an Allied expedition that set out to capture the Gallipoli Peninsula, according to a plan by Winston Churchill to open the way to the Black Sea for the Allied navies. The objective was to capture Constantinople, the capital of the Ottoman Empire, which was an ally of Germany during the war. The ANZAC force landed at Gallipoli on 25 April, meeting fierce resistance from the Ottoman Army commanded by Mustafa Kemal (later known as Atatürk). What had been planned as a bold strike to knock the Ottomans out of the war quickly became a stalemate, and the campaign dragged on for eight months. At the end of 1915, the Allied forces were evacuated after both sides had suffered heavy casualties and endured great hardships. The Allied casualties included 21,255 from the United Kingdom, an estimated 10,000 dead soldiers from France, 8,709 from Australia, 2,721 from New Zealand, and 1,358 from British India. News of the landing at Gallipoli made a profound impact on Australians and New Zealanders at home and 25 April quickly became the day on which they remembered the sacrifice of those who had died in war.
Though the Gallipoli campaign failed to achieve its military objectives of capturing Constantinople and knocking the Ottoman Empire out of the war, the actions of the Australian and New Zealander troops during the campaign bequeathed an intangible but powerful legacy. The creation of what became known as an "Anzac legend" became an important part of the national identity in both countries. This has shaped the way their citizens have viewed both their past and their understanding of the present.