ABSTRACTIn the vibrant current debate about European empires and their ideologies, one basic dichotomy still tends to be overlooked: that between, on the one hand, the plurality of modern empires of colonisation, commerce and settlement; and, on the other, the traditional claim to single and undividedimperiumso long embodied in the Roman Empire and its successor, the Holy Roman Empire, or (First) Reich. This paper examines the tensions between the two, as manifested in the theory and practice of Habsburg imperial rule. The Habsburgs, emperors of the Reich almost continuously through its last centuries, sought to build their own power-base within and beyond it. The first half of the paper examines how by the eighteenth century their ‘Monarchy’, subsisting alongside the Reich, dealt with the associated legacy of empire. After the dissolution of the Holy Roman Empire in 1806 the Habsburgs could pursue a free-standing Austrian ‘imperialism’, but it rested on an uneasy combination of old and new elements and was correspondingly vulnerable to challenge from abroad and censure at home. The second half of the article charts this aspect of Habsburg government through an age of international imperialism and its contribution to the collapse of the Dual Monarchy in 1918.