The paper presents the model “image of the otherness” as applied to the situation in the Croatian Military Frontier from the end of the 17th to the beginning of the 18th century. The centre of focus is a Habsburg officer in the Karlovac Generality and the population of this area in Croatia. The sources used in this interpretation of the conditions and the population of this Croatian area were Joseph von Rabatta’s letters, as well as reports made by various commissions and other military officers. Interest centres on the image of Croatian frontiersmen, as it emerges from the correspondence of count Rabatta, a representative of the Inner Austrian Catholic nobility originating from the County of Gorizia and the commanding general of the Karlovac Generality from 1709 to 1731. The paper attempts to determine how Rabatta experienced “Others” and what were his criteria in regard to his nuanced relationship to the “Others”. The paper attempts to examine Rabatta’s relationship to the frontier population, in view of regional and local affiliations and cultural patterns. Rabatta’s criterion, forming his opinion of the frontiersmen, was primarily determined by the goals of his service mission, i.e. fortifying the area against Ottoman inroads, establishing order in the military-frontier system and reorganising the frontier army. Rabatta developed an opinion of the frontiersmen, based on their ethnic and confessional affiliations. Rabatta was most suspicious of newly arrived frontiersmen, especially of Eastern Orthodox Vlachs. He made exceptional efforts in attempting to bring about their union with the Catholic Church. Rabatta’s unenviable role in preparing the conditions for a full-scale reform of the military-frontier system, which would take place in the mid-18th century, influenced his perception of the “Self” and “Others”.