The history of English land law can be traced back to Roman times. Throughout the Early Middle Ages, where England came under rule of post-Roman chieftains and Saxon monarchs, land was the dominant source of personal wealth. English land law transformed further from the Saxon days, particularly during the post-Norman Invasion feudal encastellation and the Industrial Revolution. As the political power of the landed aristocracy diminished and modern legislation increasingly made land a social form of wealth, subject to extensive social regulation such as for housing, national parks, and agriculture.