Constructing political identity and values is a key goal of education. This paper aims to explore the political values promoted in compulsory education in Greece. In particular, it addresses the questions: Which values are promoted in citizenship education textbooks, and what is allegedly its relationship with otherness in general? The values of Pluribus or Unum as analytical categories emerge from the theoretical framework and the research questions. Given that Greece, in the last decades, has been receiving vast flows of migrants and refugees, it is worth considering the political values that characterize the relevant school curriculum. The analysis essentially involves the textbooks of citizenship education curriculum for the last 50 years, split into two historical periods: The Dictatorship and the Metapolitefsis. The qualitative content analysis shows significant differences in the frequency by which these values are promoted in each of the two periods. During the Dictatorship the value of homogeneity, or Unum, appears most frequently, while the value of heterogeneity, or Pluribus, is further promoted during the historical period of the Metapolitefsis. It is concluded that political values in education change in favor of accepting students' diversity and healing their political trauma.