1916 Centenary: ‘Castle Document’ could have altered the Rising

A small printing press in the home of Joseph Plunkett was responsible for one of the most controversial documents in Irish history.

Intended to deceive those unaware of the intended rebellion to back the idea, it has come to be known as the Castle Document. But historians differ — and the full truth may never be known — as to how the content was decided or where it originated.

Seán MacDiarmada — Plunkett’s co-conspirator on the Irish Republican Brotherhood (IRB) military council — had sources in the intelligence world, certainly.