 The invasion was <unk> by the provisions of the Papal Bull <unk> , issued by Adrian IV in 1155 . The bull encouraged Henry to take control in Ireland in order to oversee the financial and administrative reorganisation of the Irish Church and its integration into the Roman Church system . Some restructuring had already begun at the ecclesiastical level following the <unk> of Kells in <unk> . There has been significant controversy regarding the authenticity of <unk> , and there is no general agreement as to whether the bull was genuine or a forgery . 
