reveals how King George V personally requested Irish soldiers to fight in the war due to the myth around the ‘Fighting Irish’.
Lar Joye, director of the military collection at the National Museum, said the Irish had earned a mythical reputation in Britain and America.
He said: “There is a huge tradition throughout the 19th century of the Irish joining the British army.
“There is this naive belief that the Irish make wonderful soldiers, good fighters and the kind of people you want in a tight spot. You see it also in the American armies during the American civil war. There is this kind of myth about the Fighting Irish.
“The king believed the Irish would flock to join the British army during World War One to prove they were part of the British Empire.”
Mr Joye said the 160,000 Irish men voluntarily signed up to fight in the war at Collins Barracks in Dublin.
When Queen Victoria visited Ireland in 1900, almost 40% of the British army was made up of Irish born recruits.
“At the Battle of Waterloo in 1815, it is guessed that about 50% of the British army on that battlefield were Irish born,” said Mr Joye.
The documentary explores the two decades that laid the stepping stones for the foundation of the Irish state and the claim to sovereignty.
It also reveals how Gen John Maxwell, had misgivings over putting 15 Irish rebels in front of a firing squad in 1916.
After the Rising, the Boer War general was in sole charge of the trials and sentences which resulted in the Easter Rising rebels being executed.
All seven signatories of the proclamation including Joseph Plunkett and James Connolly were shot.
will be shown tonight on RTÉ One at 10.15pm.