This thesis explores the existence and outlook of a European officer class in the mid- to later 18th century by studying the army officers of Britain and the Habsburg Monarchy from the War of the Austrian Succession to the eve of the French Revolutionary Wars. It illuminates the character of such an officer class of ‘Military Europe’ with its own cultural customs and practices. Furthermore, it details similarities, differences and peculiarities of both officer corps. This is achieved by analysing the social and national composition of both armies, with a focus here on the Habsburg Army due to the fact that it took in great numbers of foreigners and that the muster lists give an indication of how great the proportion of nobility was. A comparison with the British case shows striking similarities but also obvious differences. In a further step the ability of individuals for social advancement and national mobility is scrutinised on both sides. In this context, the state’s care for its officers and their social security is also taken into account. One possibility to acknowledge the officers’ service was to raise their status, either by ennoblement or through increasing the prestige of the uniform in court and society, its transformation into an ‘Ehrenkleid’ (garment of honour). As officers increasingly became servants to the state, rather than noble retainers and military enterprisers, they were also subject to professionalization efforts by the sovereigns. What becomes apparent, however, is that the officers did not only react to such measures but that at least a significant part of them actively worked on improving the service, thereby exhibiting a growing professionalism. In order to explore the coherence of the officer corps in those armies, with officers all following the same codes and accepting each other as equals, the thesis looks into core values (including honour, duty, courage and loyalty) binding them together and separating them from the enlisted men. The thesis will also offer a glimpse of their engagement with civilian society and culture as well as their role as ‘foot soldiers of Enlightenment’. On a European level, interaction between these officers proves their general acceptance of and respect for each other, while at the same time acting as state representatives in wartimes. Their interaction with non-European and non-state military forces and their leadership marks out the fluid boundaries of military Europe, but also exhibits the pervasiveness of European military culture.