In philosophy, the distinction between the history of philosophy and systematic philosophy has a great influence not only on the organization of teaching, but also on appointments and research funding. Above all, however, it is decisive for the self-understanding of philosophy. In recent years, the significance and function of the history of philosophy has been the subject of controversial debate. After being more or less ignored in analytic philosophy for a long time, there has been an increasing turn to the history of philosophy in recent years. Some authors even speak of a historical turn in analytic philosophy. Since the 1980s there have been growing attempts to theorize the different approaches to the history of philosophy and their presuppositions. Another focus has been on the relationship between the history of philosophy and systematic research. Numerous authors have argued for the importance of historical research for systematic philosophical research or for philosophical education. In this talk, I will be concerned with the distinction between history of philosophy and systematic philosophy itself. I am interested in how exactly this distinction is justified. So my question is: what exactly distinguishes work in the history of philosophy from systematic research? I go through the criteria proposed for this distinction and show that they are often problematic and unclear. I first address the historical distance of the authors, the significance of philosophical discourse, the question of the object of historical research and its unique method. Originality and systematicity turn out to be two essential distinguishing criteria. Ultimately, the common distinction between primary and secondary literature is also related to this. However, using two historical examples, I argue that these criteria are problematic and can hardly justify the wide-ranging distinction. In the third section, I discuss the historical origins of the division between the history of philosophy and systematic philosophy. I argue that the notions of originality and systematicity that emerged in Europe in the second half of the eighteenth century are crucial in this respect, and that these notions are still effective today, albeit unreflectively.