This thesis reinterprets Max Weber’s The Protestant Ethic and the Spirit of Capitalism using contemporary economic institutions theory as proposed by Douglass North in Institutions, Institutional Change, and Economic Performance. It shows that contrary to the accusations of his critics, Weber provides a clear mechanism for historical change which emphasizes human perceptions and changing costs. This thesis argues that Weber's approach can serve as a model for understanding other periods of historical change. This reinterpretation is used to refute Weber’s critics in explaining the continued—and widely unacknowledged—importance of The Protestant Ethic in the developing field of institutions theory, and our understanding of history.