b.1870 d.1922
Robert Erskine Childers was an Englishman, a Protestant, and an author of one of the first spy novels - The Riddle of the Sands (1903). Born in London, he fought for Britain in the Boer War in South Africa. Afterwards he resigned from service, but returned in World War I, where he served as an intelligence and aerial-reconnaissance officer and received a Distinguished Service Cross for his bravery.

While this is interesting, it's probably not enough to earn him his own node .... so here's the rest of the story:

Between the Boer War and World War I, Childers served as a clerk in England's House of Commons. There he became convinced of the need for Irish homerule. To this end, in 1914 he began smuggling guns aboard his yacht to Ireland. Returning from World War I, he traveled to Ireland, where he was elected to the Dáil Éireann as a member of the Sinn Fein political party. He also served as Sinn Fein's Minister of Propaganda.

Childers opposed the treaty that established the Irish Free State. So, after the partition of Ireland, he joined the IRA to continue the struggle for complete Irish independence. Eventually he became one of the leaders, along with Eamon de Valera, of the Republican forces in the Irish Civil War.

In 1922 he was caught in posession of a revolver by Irish Free State forces. He was court-martialed and executed in Dublin on charges of illegally possessing a handgun.

So we have:
Robert Erskine Childers - Englishman, Protestant, author, decorated British soldier and spy.
Robert Erskine Childers - Irish republican, gun smuggler, Sinn Fein politician, and IRA member.
Incidentally, his spy novel, Riddle of the Sands, was made into a movie in 1979. And his son, Erskine Hamilton Childers, was elected president of Ireland in 1973.