Following the outbreak of the Liberal Revolution, which broke out in Portugal after the revolutionary actions that happened in Porto on 24 August, and in Lisbon on 15 September 1820, a new political regime emerged and, consequently, changes in values as well as in ways of thinking and acting. It is a new conception of sovereignty with the shift of absolute power from the king to the nation. In this new imaginary signification arises the need to construct common good. In this sense, the question is posed: What is the idea of citizenship that Liberalism projected? The goals are: to interpret the specificity of the idea of citizenship, and to discuss the role assigned to instruction-education as a tool to promote citizenship. The sources are: constitutional catechisms, hygiene manuals, political textbooks, and handbooks. Regarding methodology, by reference to the Liberal Revolution, an interpretive analysis of the sources was conducted along two major dimensions and their respective descriptors: first dimension: liberal regime: constitution, state, laws, health, citizenship; second dimension: educational city: instruction-education, public education, illustration, health, citizenship. To conclude, liberalism triggered a concern with conceiving citizenship as a key factor in health promotion, and health as a crucial factor in the construction of citizenship, with instruction-education being given a fundamental role in the construction process. Citizenship in the 1820s already announced the health paradigm, which presupposes the community's and the citizen's empowerment.