It's quiet simple mate. You said you were playing as the Duke of Ulster, but there is none. Someone else said that the only Duke in Ireland is the Duke of Munster, which it isn't, there is also the Duke of Connacht, which you said you meant but never said.
So either you were playing as the Duke of Connacht or the Earl of Ulster, neither of which you said so herp derp.
Hardly worth getting into an arguement over