On a day like today, but in 1879, the Central Post and Telegraph House was inaugurated, the construction of which marked the beginning of what would later become the seat of the national government: the Casa Rosada.

This building, which would be located in front of 25 de Mayo Square and Victoria Street (currently Hipólito Yrigoyen), in the southwest corner of the site that had been occupied by the old Buenos Aires fort, was designed by Domingo Faustino Sarmiento at the end of the 19th century.

Of Italian Renaissance or Neo-Renaissance style, the Central House was in charge of the Swedish architect and engineer Carlos Augusto Kihlberg (1839 - 1908), who had arrived in Argentina in 1869 to carry out public works.

In 1872, through law Nº 556, the construction of several post office buildings was authorised, among them this Central House, whose original project consisted of a rectangular two-storey building with a courtyard in the middle. Its construction was completed in 1878 and was inaugurated on 29 January 1879 by Sarmiento's successor, Nicolás Remigio Aurelio Avellaneda, who would be head of state until 1880.

Later, in 1884, during the first presidency of Julio Argentino Roca, it began to be partially destroyed and joined to the newly built Casa Rosada by means of a central arch designed by the Italian Francisco Tamburini (1846-1891).