During the Viking Age and Early Medieval Period (c. 800-1300 AD) an extensive restructuring of Sámi settlements occurred over the vast interior region of northern Fennoscandinavia. Habitation sites were established in areas previously rarely used for settlements while simultaneously exhibiting new and distinct spatial features.The most conspicuous expression of this new settlement pattern is the hearth row sites consisting of large, rectangular hearths organized in a linear pattern. This restructuring of settlement patterns took place alongside other pronounced changes: Sámi burial customs became more unified, grave goods more elaborate and varied, while sacrifices and other ritual practices intensified significantly. These comprehensive and remarkably unified changes constitute the background to this research project. Focusing on the hearth row sites our overall aim is to understand why this restructuring of Sámi settlement and domestic space took place and to explore how it is related to other transformative processes in Sámi and neighboring societies. One crucial issue is reindeer economies and how people-animal relationships were affected and negotiated as part of these changes. Combining archaeological approaches with GIS, genetic studies and a number of environmental methods, our research reflects a broad and fresh approach to one of the most fascinating and analytically challenging periods of northern cultural history.