In 1926, a military coup led by Manuel Gomes da Costa put an end to the First Portuguese Republic. In 1933, under the leadership of António de Oliveira Salazar, a new constitution was proclaimed, the "Estado Novo". In the new, authoritarian, one-party state, strikes were declared illegal and the workers' and employers' unions came under state control. The CGT and its newspaper were banned. Many anarcho-syndicalist activists are arrested and imprisoned. In 1936, the Tarrafal concentration camp was opened on Santiago Island, in Cape Verde.