This chapter first introduces the 1179 Lateran Council and then situates it within the broader history of the papacy and medieval canon law in the twelfth century. It begins by outlining the events leading up to the council and its emergence as the resolution to a damaging schism between Pope Alexander III and Frederick Barbarossa. The chapter then provides a brief, accessible account of twelfth-century canon law and its relationship to papal government. The role played by the papacy and by local clerics in creating contemporary canon law is analysed, and an overview of current ideas and thoughts provided, including an – of necessity brief – interlude into the debates surrounding the appearance of the Decretum Gratiani in ca. 1140. The aim is to situate canon law in the history of Church government in the central Middle Ages, before moving on to discuss the nature and purpose of church councils and the twelfth–century legal theories upon which their authority rested.