Fifty-eight students at seven grade levels (kindergarten through sixth) from three population groups (urban, suburban and rural) were presented with the task of chronologically ordering a set of nine historical pictures and 'thinking aloud' about the task. The results of this study provide increased evidence regarding the kind and sources of children's historical knowledge, and how they deploy that knowledge. The most accessible historical knowledge for early and middle grade children apparently relates to changes in material culture and the patterns of everyday life. It appears, too, that the intertexts that inform children's historical understanding, especially prior to fourth grade, provide better information about material culture than about other aspects of change over time. In addition, some children at all grade levels linked history to such sociocultural issues as race and gender. Finally, by fifth grade, children were learning a new reference system that consisted of specific eras (Colonial, Revolution), events (Boston Massacre, War of 1812) and relationships (British taxes, lack of colonial representation creates pre-Revolutionary tensions) that allowed them to make more interpretations reflective of the academic discipline of history (British and colonists had legitimate but differing points of view). Children's willingness to engage in this new genre and the facility with which some students managed the transition have important implications for instruction.