Book excerpt: This volume focuses on phenomena, structures and constellations of power and rule in the 12th century from a comparative perspective. Comparing England and the Empire is a promising research project, because the Staufen and the Plantagenets ruled over more than one kingdom and claimed hegemony. Therefore, the divergence between legality and the demands of ruling over diverse lordships can be explored. The examples of extended royal rule in different constellations, treated by international authors, show how the practice of power and the structures of rule based on legitimate claims diverge.