Cornell and Hartmann (2007) developed a constructionist framework that can describe the development of racial and ethnic identities. Yet this framework has greater utility than its authors have intended as it also provides the best rubric to date for comprehending the transitions between collective identity group types. This study engages in a thorough investigation of the development of racial and ethnic identities within the context of those that precede it via an ethnohistorical analysis. It also demonstrates that this framework is capable of describing pre-modern religious and national identity types in addition to racial and ethnic identity types. This permits it to demonstrate that this framework can also be utilized in the analysis of identities and identity types in the pre-modern era, in addition to the modern examples that Cornell and Hartmann have used. To this end Weber‟s concept of the ideal type is used to support the examination of identity transitions among pre-Mexicans, Mexicans and Americans of Mexican descent in the ethnohistorical analysis. This methodological approach is in accordance with Romano‟s (1968) indication that the most effective way of understanding the way that Mexican persons define themselves is through a historical and not a sociological investigation. This investigation encapsulates the transition from pre-modern religious identities in the Iberian Peninsula, to the appearance of racial and national identities in the Viceroyalty of New Spain and the Mexican Republic. It examines a second racialization of those that lived within the northern Mexican provinces as Mexicans in the newly conquered Southwestern United States come into contact with the dominant white majority of the United States. The ethnohistorical analysis concludes with a description of the emergence of four distinct identity types among Americans of Mexican descent, each a means to combat the normative discrimination they faced.