One of the core aims of inquiry-based learning (IBL) approaches to history education is to help students grasp how historical knowledge is constructed. Thus, IBL applications are usually justified through reference to expert historians' research practices. We argue that the current body of empirical research on historians' practices is limited in some important ways. To develop an expanded understanding of the practice of historiography (i.e., historical research and writing), we interviewed 26 Finnish academic historians about activities involved in their practice. We then identified over a hundred epistemic processes of historiography that we divided into 14 categories. Some categories partly aligned with earlier accounts of historians' epistemic processes, although we identified some extensions of these categories. We also recognized five themes that provide an expanded understanding of historians' epistemic processes for IBL: archival work; tools and languages; virtues and affect; broad approaches and methodologies; and social processes. We discuss the implications of our findings for history education and argue for more diversity in studies of epistemic practices in history. Although professional historiography in its full scale cannot--and should not--be brought into all classrooms, educators need a broader understanding of historiography in order to model such a practice at different levels of education.