This thesis focuses on the politics of Antipope Victor IV and his successors Paschal III, Calixtus III and Innocent III, who were the opponents of Alexander III since the schismatic elections of 1159. The aim is to analyse the political thinking and actions of the antipopes, with an emphasis on the political relations of Victor IV. The thesis is divided into six thematic sections. The first deals with the pre-election developments and the election of 1159 itself. The second considers their position in relation to Alexander III, while the third turns to the papal-imperial policy and examines the relationship between the antipopes and Emperor Frederick Barbarossa. The fourth section discusses the status and relations of the antipopes outside the Holy Roman Empire. The penultimate chapter examines the attitude of the imperial clergy to the pontificates of the antipopes as well as the obedience of the imperial monasteries, according to papal documents. The final chapter constructs biographies of the antipopes, focusing on the period before their pontificates.