The Legacy of the True Historic Patrick (by former Irish priest, Richard Bennett)
http://www.jesus-is-lord.com/patrick.pdf
The Bull of Pope Adrian IV Empowering Henry II to Conquer Ireland. A.D. 1155
Bishop Adrian, servant of the servants of God, sends to his dearest son in Christ, the illustrious king of the English, greeting and apostolic benediction. Laudably and profitably enough thy magnificence thinks of extending thy glorious name on earth, and of heaping up rewards of eternal felicity in Heaven, inasmuch as, like a good catholic prince, thou dost endeavour to enlarge the bounds of the church, to declare the truth of the Christian faith to ignorant and barbarous nations, and to extirpate the plants of evil from the field of the Lord. And, in order the better to perform this, thou dost ask the advice and favour of the apostolic see. In which work, the more lofty the counsel and the better the guidance by which thou dost proceed, so much more do we trust that, by God's help, thou wilt progress favourably in the same; for the reason that those things which have taken their rise from ardour of faith and love of religion are accustomed always to come to a good end and termination.
There is indeed no doubt, as thy Highness doth also acknowledge, that Ireland and all other islands which Christ the Sun of Righteousness has illumined, and which have received the doctrines of the Christian faith, belong to the jurisdiction of St. Peter and of the holy Roman Church. Wherefore, so much the more willingly do we grant to them that the right faith and the seed grateful to God may be planted in them, the more we perceive, by examining more strictly our conscience, that this will be required of us.
Thou hast signified to us, indeed, most beloved son in Christ, that thou dost desire to enter into the island of Ireland, in order to subject the people to the laws and to extirpate the vices that have there taken root, and that thou art willing to pay an annual pension to St. Peter of one penny from every house, and to preserve the rights of the churches in that land inviolate and entire.
The remaining Bull here:
The Bull of Pope Adrian IV Empowering Henry II to Conquer Ireland. A.D. 1155