Maria Rosa Viseu was born in Couço in the agricultural municipality of Coruche in the Santarém District of Portugal in 1935, the eldest daughter of farming parents.
[1][2][3][4] In 1958, she attended a rally in support of the presidential campaign of Humberto Delgado, which led to the development of her political awareness and to her joining the Portuguese Communist Party (PCP).
In the following years she took part in strikes, demonstrations and other actions in her area, including protests about the electoral fraud of 1958, which ensured that Delgado would not win the election.
On 19 January 1961 she was detained by the National Republican Guard (GNR) and handed over to the PIDE, the Estado Novo's secret police.
She was elected an alternate to the central committee of the PCP and became a leader of the agricultural workers union in Santarém District.