We have seen in the greatest Irish contributions of the world that the strength of Ireland lied in the exceptional expressiveness of Irish people, making them outstanding singers, writers, actors, comedians and politicians. Irish people have often achieved fame abroad, particularly in the USA and Australia. This thread aims at determining who was the greatest Irish person ever (from Ireland).

That's a remarkably difficult contest due to the number of famous people represented in similar categories (mostly actors, comedians and writers as you will see in the Wikipedia list of Irish people).

The choice is all the harder for me for I don't care much about poetry or even (fiction) literature, and I am reluctant to give the title of greatest person ever to an actor, comedian or singer. The most famous Irish writer is probably Oscar Wilde though.

In business, the greatest Irish entrepreneur was perhaps Tony Ryan, founder of the pan-European discount airline Ryan Air, although he didn't found it all by himself.

In the military and politics, the most celebrated Irishman is Arthur Wellesley, 1st Duke of Wellington, who defeated Napoleon at Waterloo and briefly served as British Prime Minister. However, he was essentially of English descent and just happened to be born in Ireland.