Coniston massacre
The Coniston massacre, which took place near the Coniston cattle station in the then Territory of Central Australia (now the Northern Territory) from 14 August to 18 October 1928, was the last known officially sanctioned massacre of Indigenous Australians and one of the last events of the Australian Frontier Wars. People of the Warlpiri, Anmatyerre, and Kaytetye groups were killed. The massacre occurred in revenge for the death of dingo hunter Frederick Brooks, killed by Aboriginal people in August 1928 at a place now known as "Yukurru", also known as Brooks Soak.
Rory O'Connor (Irish republican)
On 8 December 1922, along with three other republicans Liam Mellows, Richard Barrett and Joe McKelvey captured with the fall of the Four Courts, Rory O'Connor was executed by firing squad in reprisal for the anti-treaty IRA's killing of Free State TD Sean Hales. The execution order was signed by Kevin O'Higgins. O'Connor had been best man at his wedding on 27 October 1921. The killing remains as a symbol of the bitterness and division of the IRA's Civil War. O'Connor, one of 77 republicans executed by the Cumann na nGaedheal government of the Irish Free State, is seen as a martyr by the Republican movement in Ireland.