Some things which happened on this date:

1260 - Brian O'Neill, during the assault on the Earldom of Ulster, is defeated and killed by the forces of Roger des Auters at the battle of Down (renamed by de Courcy as Downpatrick)
1660 - Charles II is proclaimed king in Dublin, six days after London, thus ending Cromwell's reign as Lord Protector and beginning a brief and limited Catholic Restoration
1730 - Sir Edward Newenham, popular MP for County Dublin and strong advocate of the American colonists, is born. Newenham is introduced at the court of Louis XVI by the Marquis de Lafayette, even though Britain and France are at war
1755 - George Barrington (real name Waldron), writer, adventurer and pickpocket is born in Maynooth, Co. Kildare. A well-dressed pickpocket who "worked" in Churches and the Houses of Parliament, he is arrested and transported to Australia. Later, he becomes Australian high constable. He is known for the lines: "True patriots all; for be it understood- We left our country for our country’s good"
1784 - Foster's Corn Law regulates the corn trade
1784 - The Irish Post Office, distinct from English and Scottish services, is established by statute
1865 - The last surviving member of the Irish House of Commons, Sir Thomas Staples, who had risen in his profession to be Queen's Advocate for Ireland, dies in Lissan, Co. Tyrone 11 weeks short of his 90th birthday

Ah Brian Ó Néill, he was one of the three individuals declared High-King after the Ruaidhrí Ua Conchobhair. A smartie for anyone able to name the other two.

Muircheartach mac Cathal mac Dermot mac Tadhg, and Giolla na Naomh O Mulvihill of the Tuathas, riadach?

Ard-Taoiseach wrote:

Muircheartach mac Cathal mac Dermot mac Tadhg, and Giolla na Naomh O Mulvihill of the Tuathas, riadach?

Not that I am aware of. I'll give you a clue, neither of them were Irish.

riadach wrote:

Ard-Taoiseach wrote:

Muircheartach mac Cathal mac Dermot mac Tadhg, and Giolla na Naomh O Mulvihill of the Tuathas, riadach?

Not that I am aware of. I'll give you a clue, neither of them were Irish.

Henry II and Edward DeBruce?

Ard-Taoiseach wrote:

riadach wrote:

Ard-Taoiseach wrote:

Muircheartach mac Cathal mac Dermot mac Tadhg, and Giolla na Naomh O Mulvihill of the Tuathas, riadach?

Not that I am aware of. I'll give you a clue, neither of them were Irish.

Henry II and Edward DeBruce?

Half right. Henry II took the submission of Irish chiefs, but was never declared high-king. Try again.

riadach wrote:

Ard-Taoiseach wrote:

riadach wrote:

Ard-Taoiseach wrote:

Muircheartach mac Cathal mac Dermot mac Tadhg, and Giolla na Naomh O Mulvihill of the Tuathas, riadach?

Not that I am aware of. I'll give you a clue, neither of them were Irish.

Henry II and Edward DeBruce?

Half right. Henry II took the submission of Irish chiefs, but was never declared high-king. Try again.

Bah! Was he called Hugh?

Nope, his name did begin with a H though, he was not a henry however.

riadach wrote:

Nope, his name did begin with a H though, he was not a henry however.

All I can find is two, Edward DeBruce and the above-mentioned.

There was also King Haakon IV of Norway.

riadach wrote:

There was also King Haakon IV of Norway.

Really? He claimed the Irish throne? Mad.

Ard-Taoiseach wrote:

riadach wrote:

There was also King Haakon IV of Norway.

Really? He claimed the Irish throne? Mad.

Not so much. It was offered to him in exchange for him fighting against the English. He was currently engaged in a campaign reasserting Norwegian control over the Western Isles and the Isle of Man. Any port in a storm will do for us Irish.

riadach wrote:

Ard-Taoiseach wrote:

riadach wrote:

There was also King Haakon IV of Norway.

Really? He claimed the Irish throne? Mad.

Not so much. It was offered to him in exchange for him fighting against the English. He was currently engaged in a campaign reasserting Norwegian control over the Western Isles and the Isle of Man. Any port in a storm will do for us Irish.

Clever, I thought our engagement with Scandinavia began and ended with the Vikings. I would've never thought of the Norwegian king. Very interesting. Thanks for bringing that to light, riadach.

Ard-Taoiseach wrote:

riadach wrote:

Ard-Taoiseach wrote:

riadach wrote:

There was also King Haakon IV of Norway.

Really? He claimed the Irish throne? Mad.

Not so much. It was offered to him in exchange for him fighting against the English. He was currently engaged in a campaign reasserting Norwegian control over the Western Isles and the Isle of Man. Any port in a storm will do for us Irish.

Clever, I thought our engagement with Scandinavia began and ended with the Vikings. I would've never thought of the Norwegian king. Very interesting. Thanks for bringing that to light, riadach.

It was a blip on the radar really. This was when the Irish rally was gaining full pace. The weaknesses of the English were becoming apparent (their divisions during the baron wars must have been felt in Ireland) and their polity was becoming as divided as the native one. This would be later accelerated by the Bruce invasion.