Roger Casement was hanged in August 1916 for treason against the Crown. Formerly Sir Roger, his assistance to Germany during the First World Ward was undeniable and from a British point of view he was a traitor.
From from an Irish nationalist point of view, he was a rebel and a hero who now took his place in history among the martyrs of republicanism and the leader of the 1916 Rising.
No knight of the realm had faced treason charges for centuries, let alone be executed. His story was without precedent.
A Protestant Anglo-Irish man who had been a loyal servant of the British empire, he had exposed horrific abuses of indigenous people in Africa and South America. But he then came to believe Ireland urgently needed to free itself of Britain.
Who was this complex individual and how did he end up being killed by the state he had served?
Casement is a subject of a new book – A Rebel And A Traitor – by Rory Carroll, the Guardian's Ireland correspondent.
He joined Sam McBride on the BelTel.