Public health acquired a prominent role in Portugal in 1834 with the establishment of Liberalism. Following European trends, the "statistical liberalism" strengthened the Portuguese State, with numbers underpinning political decisions. In 1837, the Council of Public Health required that all burials should be carried out in public cemeteries. Therefore no one (at least in theory) could be buried without a certificate (bilhete de enterramento) signed by a doctor and stating the cause of death. This article aims to catalogue and analyze the main documentary corpus on individual-level causes of death produced in Portugal between 1834 and 1910, when the Republican regime was implanted leading to the formation of the civil register in 1911. In a second phase, we use samples of the individual records to understand their quality in terms of territorial coverage and the quality and systematization of the information on causes of death. At this point we particularly aim to recognize whether the declaration of diseases followed the official nomenclature or whether doctors used their own classifications. It is important to mention that one of the samples is the city of Oporto for which our team has worked extensively. To analyze the quality of the sources, we make use of a wide set of information, such as parish death registers, population statistics charts, aggregate charts of causes of death, legislation and official correspondence.

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