APRIL 25 was officially named Anzac Day in 1916.
It was marked by a wide variety of ceremonies and services in Australia, a march through London, and a sports day in the Australian camp in Egypt.
In London, more than 2000 Australian and New Zealand troops marched through the streets and a London newspaper headline dubbed them "the knights of Gallipoli".
Marches were held all over Australia; in the Sydney march, convoys of cars carried wounded soldiers from Gallipoli attended by nurses.
For the remaining years of the war, Anzac Day was used as an occasion for patriotic rallies and recruiting campaigns, and parades of serving members of the AIF were held in most cities.
During the 1920s Anzac Day became established as a national day of commemoration for the 60,000 Australians who had died during the war.
In 1927, for the first time, every state observed some form of public holiday on Anzac Day.
By the mid-1930s, all the rituals now associated with the day - dawn vigils, marches, memorial services, reunions, two-up games - were firmly established as part of Anzac Day culture.
With the coming of the Second World War, Anzac Day also served to commemorate the lives of Australians who died in that war.
In subsequent years the meaning of the day has been further broadened to include Australians killed in all the military operations in which Australia has been involved.