The parents of my great grandma are Francisco Peixoto de Mattos (b. 6 May 1841, Candelária, Madalena), and Rosa de Medeiros Silva (b. 4 July 1846, Nossa Senhora Mãe de Deus, Povoação), married on 6 November 1866, São Francisco Xavier, Rio de Janeiro.
She is the daughter of José Furtado Sardinha (b. unknown) and Maria de Medeiros Silva (b. unknown, probably in Água Retorta), married on 5 May 1838, Água Retorta, Povoação. Any further details on this couple is welcome as I did not manage to find their birth dates.
His parents are José Furtado Sardinha (b. 9 April 1779, Água Retorta) and Anna de Medeiros Frias, (8 March 1780, Faial da Terra), married on 28 September 1803 in Faial da Terra, Povoação. Sorry, I switched their marriage date around :)