6 October 1175: The Treaty of Windsor was agreed between representatives of Rory O'Connor [above] the High King of Ireland (Ruaidrí Ua Conchobair an Ard Rí na hÉireann) and King Henry II of England on this day. King Rory was the last High King of Ireland.

King Henry forced him to submit as a result of the Anglo- Norman Invasion of 1169 and King Henry’s own Expedition to Ireland in 1170/71. Basically the King of Ireland eventually submitted to circumstances and recognised Henry II as his Overlord.

The negotiations were conducted at Windsor in Berkshire, England.

The Treaty began:

This is the agreement which was made at Windsor in the octaves of Michaelmas [October 6] in the year of Our Lord 1175, between Henry, king of England, and Roderic [Rory], king of Connaught, by Catholicus, archbishop of Tuam, Cantordis, abbot of Clonfert, and Master Laurence, chancellor of the king of Connaught, namely:

The King of England has granted to Roderic [Rory], his liegeman, king of Connaught, as long as he shall faithfully serve him, that he shall be king under him, ready to his service, as his man. And he shall hold his land as fully and as peacefully as he held it before the lord king entered Ireland, rendering him tribute. And he shall hold his land as fully and as peacefully as he held it before the lord king entered Ireland, rendering him tribute...

The witnesses are Robert, bishop of Winchester; Geoffrey, bishop of Ely; Laurence, archbishop of Dublin; Geoffrey, Nicholas and Roger, the king's chaplains; William , Earl of Essex; Richard de Luci; Geoffrey de Purtico, and Reginald de Courtenea.

This Treaty marked the end of an era in Irish History as Ireland was no longer seen as a distinct kingdom

- but a Lordship under English domination.