It was formed as part of a larger Church effort to "re-Catholicize" Brazil after a period of increased secularism and liberalism in Brazilian society in the aftermath of World War I.
The early populist policies of the new government under Getúlio Vargas (1930–1945) accelerated the decline of the traditional authority of the landed aristocracy and the Church.
Their Constitutionalist Revolution failed, but in response, Getúlio Vargas convoked a constitutional assembly to revamp the country's political organization.
Cardinal Sebastião Leme, Archbishop of Rio de Janeiro and leader of the Brazilian bishops, sanctioned the plan, and soon the League was active all over Brazil.
[3] Olveira, now secretary-general of the Archdiocesan Board of the League in São Paulo, was chosen by Cardinal Duarte Leopoldo e Silva as a Catholic coalition candidate to the constitutional assembly.