Isaac Prilleltensky's (2003) concept of psychopolitical validity stresses the need to consider both the political and the psychological nature of power in the study of wellness, oppression, and liberation. The authors advocate that psychopolitical validity would be strengthened if it included an explicit appreciation of historical context. The inclusion of historical knowledge offers a greater insight into how power has been exercised to promote and maintain oppression, as well as helps to identify methods for working towards social justice. The authors illustrate how the dynamics of power change over time by using examples of how the field of psychology (including community psychology) treated two historically oppressed groups: African Americans and women. Consistent with epistemic validity, investigation into the history of these two groups demonstrates how the role of psychological research has both contributed to the oppression of others, as well as promoted social change. Consistent with transformative validity, these examples illustrate how marginalized groups can work within an oppressive system to challenge the status quo and, in turn, change their position in society. (Contains 1 figure.)