Career
João Duarte de Sousa served as a secretary in the Velas municipal hall from 1886, a post he held for 24 years. Later, he would become the Secretary of the Polícia Repressiva da Emigração Clandestina (Repressive Police for Clandestine Emigration), a post in which he was very unpopular for his political conflicts and the way in which he exercised his position of authority. Interested in local history, he completed several investigations within the municipal archives, resulting in his published work Apontamentos Históricos e Descrição Topográfica, of which many were republished in the newspapers of São Jorge and Terceira.
The publication of his book, resulted in conflict with his political adversary (and successor in the Angra do Heroísmo municipal council), the Jorgenese José Cândido da Silveira Avelar.
João Duarte died in Angra do Heroísmo on 29 May 1909, at the age of 46.