On 8 November 1320, Estêvão da Guarda and his wife, Sancha Domingues, founded a chapel at the São Vicente de Fora Monastery, Lisbon. Two years later, a confirmation document details every aspect related to the chapel administration and worship (AML, 2003, p. 41). In fulfilment of the founders’ wishes, succession to the administration of the assets fell on the eldest male heir. Thus, after the death of Estêvão da Guarda, it fell on Álvaro Afonso, the grandson of Estêvão and Sancha.
However, the chapel and related properties remained in the lineage’s administration for only two generations. The disowning of the great-grandson, Diogo Álvares, in 1419 by order of João I, seems to indicate irregularities on the part of the founders’ successors (AML-AH, Chancelaria régia, Livro dos Pregos, doc. 285, ff. 200v-201v). For an extended period, the “problematic and troublemaking” administration was met with a lack of income, as attested by a document dated December 1513 (MARTINS, 1999, p. 11). This document reveals a poorly kept chapel, “so badly looked after that it looked abandoned” (AML-AH, Casa de Santo António, Livro da instituição da capela de Estêvão da Guarda, doc. 15; MARTINS, 1999, p. 12). For these reasons, on 26 July 1512, King Manuel ordered the senate of Lisbon’s municipal council to take possession of the chapel, and gave it the right to appoint and remove its administrators (AML-AH, Casa de Santo António, Livro da instituição da capela de Estêvão da Guarda, doc. 1, f. 5). It should be noted that the founders had foreseen the possibility that, in case there was no descendant in the family, the administration of the chapel would be handed over to a citizen of Lisbon, appointed by the city council (MARTINS, 1999, p. 28). This context serves to explain the fact that the municipality currently keeps most of the documentation relating to this entail. Thus, it is in Lisbon’s municipal archive (Arquivo Municipal de Lisboa) that both the will of the founders and the documents of the institution and ratification are preserved, transcribed in an eighteenth-century codex named “Livro da Instituição da Capella de Estevão da Guarda, e outras cartas (…)” (AML – AH, Casa de Santo António, Livro da instituição da capela de Estêvão da Guarda, docs. 1-16).