Barreto was one of the founders of Portuguese trades union confederation, the CGTP, some five decades earlier, and died on 30 October 2020 in Castanheira de Pera, fourteen days after his 88th birthday.
He participated in initiatives to oppose the then long-term dictatorship of António Salazar and Marcelo Caetano, as a member of the support committee for the candidacy of General Humberto Delgado to the Presidency of the Republic of Portugal, in 1958.
[1] After actively participating in the formation of the Intersindical Nacional (National Intersindical_, and later the General Confederation of Portuguese Workers (CGTP),[1] in 1970, Kalidás Barreto led the Sindicato dos Têxteis do Centro (Textile Union of the center), and was the national director of CGTP and technical advisor for Portuguese missions to the International Labour Organization (ILO).
[1] He contributed to the regional press, mainly to newspapers in Castanheira de Pera and in the neighbouring municipalities of Figueiró dos Vinhos and Lousã, was an associate provider for the National Institute for the Use of Free Times (INATEL) and has authored several books.
[1] He was the beneficiary of the National Institute for the Use of Free Time or Instituto Nacional para o Aproveitamento dos Tempos Livres (INATEL).