This chapter interprets Pope Nicholas I and his pontificate on the basis of his interactions with the Franks. The sheer scope of these activities tells us something about Nicholas's pontificate. The chapter also discusses three cases where Nicholas and the Franks were engaged in a concerted fashion over several years in each instance. The first case study considers the attempt by Lothar II to divorce his wife Theutberga in order to marry his long-time consort, Waldrada. The second case concerns Nicholas's role in the seemingly interminable quarrel between Hincmar of Reims and Bishop Rothad of Soissons. The third and final case concerns another quarrel involving Hincmar and Nicholas. The chapter also explores what was the relationship between Nicholas and Anastasius Bibliothecarius, and what was the relationship between Nicholas and the Pseudo-Isidorian forgeries that defended the rights of suffragan bishops against their metropolitans.