Beginning in the late 1160s, and in the space of a few short years, the face of Ireland was transformed and the course of Irish history irrevocably changed. The English invasion effected a revolutionary metamorphosis on the landscape of Ireland, bringing enormous changes in patterns of landholding and methods of land exploitation; there followed an agricultural and economic transformation, and the introduction of a whole new social system affecting everything from the laws people used, to the homes they lived in, to the food they put on the table. Of course, it was by no means the case that all of Ireland felt the impact of these developments. Change was confined to those parts of the country successfully exposed to English colonization, which, as we shall see, never affected the entire island. Furthermore, while the events of the late twelfth century were clearly momentous, it would be wrong to underestimate the degree to which there was some form of continuity from the pre-invasion period.