[4] The origins of the Alfândega Square date back to the end of the 18th century, when the area where it is located today served as the city's old river port.

On July 2, 1783, the councilors of Porto Alegre ordered the construction of a stone pier by the Guaíba Lake to facilitate the arrival of passengers and goods.

[5] In 1804, the then governor of the Captaincy of São Pedro do Rio Grande do Sul, Admiral Paulo Gama (future 1st Baron of Bagé), ordered the expansion of the anchorage with the construction of a pier, which was considered a remarkable work for its dimensions, with 24 pillars of stone entering the waterway, allowing the landing of sumacas (small two-masted boats) and large yachts.

Silvestre de Sousa had his concession revoked, and the public administration ordered that the access to the pier and the Customs should be cleared of street vendors and temporary constructions.

The situation, however, only really improved when, between 1856 and 1858, a stone wall with stairs was erected by the river, on the alignment that today corresponds to Sete de Setembro Street.

[5][7] In 1912, in order to meet the port improvement and sanitation policy of the city, the demolition of the old Customs building and a hundred-meter wide embankment into the Guaíba Lake consolidated the current configuration of the square and made possible the construction of the Tax Station (now MARGS) and Post and Telegraphs (now Memorial of Rio Grande do Sul) buildings, as well as the Mauá Pier, transformed into the main commercial warehouse between the interior of the state and abroad.

In 1923, the Monument to General Osório was installed in the center of the area, with an equestrian statue, water mirrors, benches and fountains, made by sculptor Hildegardo Leão Veloso.

[5] The presence of streetcars, first pulled by donkeys, then powered by electricity, was responsible for the great circulation of pedestrians in the Alfândega Square, attracted by its proximity to cafés, restaurants, movie theaters, clubs and hotels.

[5] In 1979, the Porto Alegre City Council approved a law that unified the squares Senador Florêncio and Barão do Rio Branco, absorbing the stretch of Sete de Setembro Street and turning it into a pedestrian walkway.