His collected papers are kept in the Archive-Museum of Brazilian Literature, part of the Fundação Casa de Rui Barbosa.
Castelinho, as he was known, was born Teresina, in the Brazilian State of Piauí on June 25, 1920, the son of Cristino Castello Branco and Dulcila Santanna.
It was read, appreciated and feared by politicians, since it was written by someone intimate with the backstage dealings of power and a shrewd interpreter of the political reality.
During his leadership of the Union, Castello constantly confronted the junta, but doing it with diplomacy, trying not to create friction.
After the issuing of Institutional Act Number 5 (Ato Institucional Número Cinco, in Portuguese) by the military dictatorship, the press in Brazil was severely censored and restricted.