No it didn't fool, as the treaty of Windsor (1175) did not give all of Ireland to EnglandThe Treaty of Windsor established Rory's kingdom as a vassal state of England. This did not include Leinster.
Where is this sovereign all island kingdom of Ireland you speak of, and when did it exist?
- read post 98 above and learn.
The historical fact remains - the king of England, Henry II, signed the treaty of Windsor (1175) with the High King of Ireland, Ruaidrí Ua Conchobair - which recognised the country Ireland, as being one entity - and the Kingdom of Ireland, as having one High King.
Treaties are signed between heads of State and countries.
Suck it up.