The use of evidence in history is important as it employs problem solving and thinking skills through the selection and evaluation of evidence. The authors discuss the research in the field of the use of evidence and prior knowledge in history education. All of the studies had one thing in common, the fact that there was only one correct solution in each of the tasks. However, in life and in the domain of history, it is common to have uncertainty, where there is more than one possible correct answer in the tasks being studied or lived. According to the authors, research about evidence evaluation has primarily been in the context of scientific thinking and the effect of content domain has been overlooked. The purpose of the author’s research is to study the evidence-evaluation skills of subjects who have high domain specific knowledge in relation to an ill-defined task within a historical context. The authors focused on the forced expulsion of the Moriscos people from Spain in 1609, when they refused to convert to Catholicism. The research is part of a larger research project, which studies the interaction between reasoning and domain-specific knowledge. The authors discuss the objectives, subjects, procedure (parts one and two), and provide descriptions of historical documents and the results. They conclude with a discussion of the results.