When World War I broke out in 1914, Australian men flooded recruiting stations to join up.
Among them was a group of men who tried to join without success.
Aboriginal people were officially refused permission to enlist on the grounds of race, although the Australian War Memorial said that some "slipped through the net".
As the war dragged on and casualty lists grew longer, things changed.
"By October 1917, when recruits were harder to find and one conscription referendum had already been lost, restrictions were cautiously eased," the AWM said.
A military order was issued: "Half-castes may be enlisted in the Australian Imperial Force provided that the examining medical officers are satisfied that one of the parents is of European origin."
As a result, more than 400 Aboriginal soldiers fought in WW1. St George's Cathedral will pay tribute to Aboriginal soldiers with an exhibition and new memorial to be dedicated tomorrow.
Precentor of St George's Cathedral, the Rev. Graeme Napier, said research for the church indicated at least 76 Aboriginal soldiers were born in WA or had enlisted in the State.
The exhibition and memorial dedication were timed to coincide with NAIDOC Week.
It would also commemorate the battle of Hamel, in which Australian and American soldiers fought together for the first time on July 4, 1918.
Mr Napier said it was time that the contribution of Aboriginal soldiers was properly recognised and acknowledged.