Born in Sandycove, Co. Dublin, the son of Captain Roger Casement of the 3rd Dragoon Guards of the British army and Anne Jephson from Mallow, Co. Cork. His mother had him secretly baptised in her own religion, Roman Catholic, but he was raised in the Protestant faith of his father. As both his parents died young, Roger was taken in by an uncle, near Ballycastle, Co Antrim, and educated as a boarder at the diocesan school in Ballymena.
From 1895 onwards he held consular appointments at various locations in Africa, including Boma in the Congo (1904), where for the British Foreign Oﬃce he investigated Belgian human rights abuses of the indigenous people. Later, in Peru he was commissioned to undertake a report on the reported abuse of workers in the rubber industry in the Putumayo basin, which earned him a knighthood after his findings were published as a parliamentary paper (1911).
Casement had been a member of the Gaelic League and became increasingly radicalised by the opposition of the Ulster unionists to Home Rule from 1912 onwards. Casement wrote nationalist articles under the pseudonym ‘Seán Bhean Bhocht’.
He raised funds for the Irish Volunteers in the United States and was arrested at Banna Strand in Co Kerry on Good Friday 1916 while trying to land arms secured from Germany.
Before being tried for high treason at the Old Bailey, British officials circulated diaries, supposedly written by Casement, which detailed homosexual activity — presumably to discredit him as an ‘Irish martyr’. He was unmarried.
Having being found guilty, Casement was hanged at Pentonville Prison on August 3 1916 — the only leader of the Rising to be executed outside of Ireland. His bones were returned to Dublin and buried at Glasnevin in 1965.