During the military regime known as the "Revolución Libertadora" that had deposed Perón's government in 1955, in 1957 and before the elections that was to be held in 1958, a Constitutional Convention was elected to reform the constitution. This reform does not include 1949's, implicitly annulling it so the text was based on the 1898 one. The only changes done were to include a summary of Perón's social articles known as "article 14 bis" (existing currently) and to establish the necessity to have a Labour and Social Security Code.