Casement , Sir Roger David (1864–1916), a British colonial administrator and Irish nationalist. During World War I, he tried to win German support for the Irish independence movement. In 1916, when the British government found out about his efforts, he was arrested and charged with treason. He was convicted and hanged in August, 1916. Before his execution, Casement's opponents privately circulated diaries, allegedly written by him, containing descriptions of homosexual activities. This further damaged his reputation, and prevented him from being granted a reprieve. Casement's supporters charged that the diaries were forgeries, but they are now believed to be authentic.

Casement was born in Kingstown, Ireland. He was a member of the British consular service, 1895–1911. From 1901 to 1904, he served in the Congo Free State, gaining recognition for exposing the exploitation of native workers by Belgian landowners. While serving in Brazil, 1908–1911, he reported to the British government on atrocities committed there by employees of a British-owned company. He was knighted in 1911.