This space with the two pillars is called Piazzetta San Marco – Piazzetta meaning Small Square – which represents a sort of entrance to the famous Piazza San Marco. On top of the pillars stand the two patrons Venice: the winged Lion representing Saint Mark and the might of the Venetian Republic, and saint Theodore slaying the dragon, ancient protector of the city of Venice.
They arrived in Venice in the XI century, but spent over a century lying on the ground because no one really knew how to erect them due to their weight and size. It was only in 1172 that an engineer called Nicolò Barattieri had the idea of repeatedly wetting the hemp ropes tied to the pillars with water, which would then shrink and tighten, thus heaving them up to how we see them today. As a personal reward, the city allowed Barattieri to practice gambling in the space between the two columns, gambling being strictly illegal anywhere else in the city. After his death, the space between the pillars became the venue of gruesome public executions, as a warning to the population.