This article challenges the tradition in much history education research of privileging teachers' content knowledge--and within this area, their understanding of evidence and epistemology--in explorations of the knowledge shaping their pedagogical reasoning and practice. Moving away from the normative statements that often follow from this emphasis, it offers an empirical examination of how four secondary-level teachers in England made pedagogical decisions, using their efforts to cultivate students' historical empathy as an illustration. In this study, the history teachers employ thirteen different types of knowledge that are categorizable as student factors, structural factors and teacher factors, and deploy the types in combination as "knowledge packages" responsive to changing circumstances. Any one of the relevant elements of teacher knowledge--from student preconceptions to capacities, curricular resources to time, teachers' energy level to command of subject matter--might take precedence and determine the curriculum at a given moment. These findings give weight to an emerging strand of history education scholarship that strives to holistically capture the nuance and variability in teachers' thinking, rather than focusing narrowly upon one aspect of it. (Contains 1 table and 7 notes.)