Repetition has long been an important tool in such fields of humanities research as literary studies and art history, in which scholars repeatedly return to texts and images to develop critically engaged understandings. Historians also need to adopt repetition as a distinct methodology, particularly in relation to the material world. Repetitive engagement with the material world has the potential to open up new research avenues for historians, through a greater awareness of the questions prompted by things. It also provides a means of developing much-needed material literacies and extending and expanding modes of attention.

The recent surge in computing power and access to data-processing software and online resources enables historians to capture historical statistics on a much larger scale than before. The data revolution—encompassing unprecedented advances in data transcription, augmentation, and collaboration—is especially valuable for studying the history of regions where written records are scarce, such as sub-Saharan Africa. The digitization of large numbers of colonial and postcolonial records offers much promise for a greater understanding of Africa’s economic past.

The role of centurions in Roman warfare has never been decisively established. Historical sources suggest that centurions exerted an influence on the performance of the Roman battle line that was highly disproportionate to their numbers, as well as to their particular actions. However, the lack of a formal framework of Roman tactics does not allow this proposition to be tested. The results obtained from an agent-based model ( abm ) of Roman warfare, a computer-simulation technique, however, suggest that battle formations benefited greatly from the presence of even a small percentage of psychologically resilient soldiers, especially along the first line, even if these individuals displayed no more than average levels of skill and aggression. Hence, the model’s simulated patterns of Roman warfare indicate that the multiple roles performed by the centurions as described in the sources were not distinguished so much by tactics as by experience and imperviousness to the stress of combat.

Analysis of the coinage during Nero's reign as Roman emperor reveals a much less uniform image of Nero than is usually depicted in historical literature. The case of Nero exemplifies the importance of an interdisciplinary methodological framework. A “pick and mix” numismatic methodology devised in support of a Neronian ideology gleaned via literary evidence may lead to a superficially convincing image of the emperor, but it will not do justice to the complexities surrounding his reign.

White killers of African Americans in New Orleans between 1921 and 1945, nearly half of whom were policemen, insisted that they acted in self-defense, only after their victims had threatened them, often by reaching for weapons. But many of their victims were unarmed. The conventional interpretation is that white residents invoked a formulaic justification of self-defense to mask their real intention, to uphold the city's racial hierarchy. Recent studies by cognition researchers, however, suggest a more complicated interpretation—that endemic racism can influence how the brain processes information, even to the extent of causing people to see a weapon where none exists.

The timing of the American frontier's closing can be determined through an analysis of the patterns and rates of settlement growth in the United States—based on historical county boundaries, population data from U.S. censuses, and a minimum of two people per square mile to classify a region as settled. Trends in the settlement of the contiguous areas of the country indicate three periods of population settlement—1790 to 1840, 1840 to 1910, and 1910 to 1990. The first period of rapid frontier growth ended in 1840, and a second, more moderate, one ended in 1910, marking the final closure of the frontier.

Comparison of probate inventories with the findings of archeological research shows that neither, by itself, gives a complete account of eighteenth-century material culture. Data from excavations and inventory studies in Delaware illustrate how these sources can be used together to gain a better understanding of life. Archaeology provides particularly important data on poor households.