"Irish prince" could be 'prionsa Gaelach'/'prionsa Éireannach'; To say "Irish blood" you would say "Fréamh den Éireannach"; as in "He has Irish blood in him." which would translate as "Tá fréamh...
Most probably because of the 1916 rising and events leading up to this, whereby the Irish rebels fought against the British rule and brought independence to Ireland.